Re: [ccp4bb] Confusion about space group nomenclature

[Bernhard Rupp]

>@ Ian: 

Not quite, here's a table giving the complete list of the 3 types:

http://pd.chem.ucl.ac.uk/pdnn/symm3/allsgp.htm

Yes, this Table is known and agrees with what I wrote. 

I still do not like, to the point of vehement opposition, the use of 
enantiomorphic for the entire 65 because of the point made below @Jens 

 

@ Boaz:

> the most general, analytical, mathematical one-word definition of this 65 
> sg's or something that will bring the message as clearly (in the practical 
> sense) to students

 

Yes. One word. Succinct. Clear. Context-insensitive. Un-mis-interpretable. 
…wishful thinking.

 

@ Jens:

> I think the precise and correct term applicable to the "65" should be 
> pro-chiral spacegroups. They are not chiral by themselves, but addition of 
> "something" /allows/ for the creation of a chiral object (i.e. the crystal).

For a moment I though we have it…. but then the rest would be anti-chiral? 

 

Again, if we care about structure, then the word should address what the space 
group does (or does not) to the motif.  This clashes already with the fact that 
the members of an enantiomorphic pair are themselves called enantiomorphic or 
chiral, because they do not morph the subject. This was the point in my 
original post, and we are not any closer. I give up.

 

But not without throwing another one:

 

What are we supposed to do with the poor 3 space groups that are their own 
enantiomorph?

Are they bi-enant? Or trans-enant?

 

Enough of this thread.

 

Over and out, BR

 

 

 

Re: [ccp4bb] How to get a CIF configure for a designed ligand

[Tim Gruene]

-BEGIN PGP SIGNED MESSAGE-
Hash: SHA1

Dear Robert,

this is what I just did:
1) went to en.wikipedia.org and entered your ligands name Dibenzothiophene
2) copied the SMILES string provided for many small molecules in Wikipedia
3) went to http://http://grade.globalphasing.org and paste the SMILES
string
4) downloaded the CIF-file

Altogether it took longer to write this email than to get the
cif-file, which is why I find the grade server so useful :-)

Best regards,
Tim

On 05/02/2014 06:46 AM, Robert wrote:
> Dear all, How can I get a cif configure for a new ligand. Right
> now, I want to use the phenix to refine a complex structure. But I
> found that I cannot get the ligand cif file from the CCP4 search.
> The ligand is dibenzothiophene. So do you have any idea to help me.
> Thanks very much for your help. Best wishes.
> 
> 
> 
> 
> Robert.
> 

- -- 
- --
Dr Tim Gruene
Institut fuer anorganische Chemie
Tammannstr. 4
D-37077 Goettingen

GPG Key ID = A46BEE1A

-BEGIN PGP SIGNATURE-
Version: GnuPG v1.4.12 (GNU/Linux)
Comment: Using GnuPG with Icedove - http://www.enigmail.net/

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Nvrx5xUF0yrCRZkTKrrKNgI=
=JD49
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[ccp4bb] verifying protein crystal content by mass spectrometry or SDS-PAGE

[sreetama das]

Dear All,
   Is there any protocol for preparing a sample from 
(cleaning/dissolving) protein crystals for verifying their mass through mass 
spectrometry or SDS-PAGE? How many protein crystals are required? Should they 
all be from the same well, or can they be from different wells with slight 
changes in protein concentration/precipitant concentration/ pH? Should the 
crystals be cleaned with the reservoir solution and then dissolved in the 
protein buffer?


I am getting very thin, needle-like crystals which are too tiny for mounting. 
Adding Izit dye has also not been conclusive. Similar looking crystals have 
appeared in 3 conditions. Changing 
precipitant concentration, protein concentration, pH , and seeding have 
made no difference so far. I wish to determine whether the full protein is 
crystallizing, or only some fragment. The protein molecular weight is ~22KDa, 
and the crystals take ~3 weeks to grow. 


Thanks in advance,
sreetama

Re: [ccp4bb] How to get a CIF configure for a designed ligand

[heisenbergzz]

prodrg should work

Robert  wrote:
>Dear all,
>How can I get a cif configure for a new ligand. Right now, I want to
>use the phenix to refine a complex structure. But I found that I cannot
>get the ligand cif file from the CCP4 search. The ligand is
>dibenzothiophene. So do you have any idea to help me. Thanks very much
>for your help.
> Best wishes.
>
>
>
>
>Robert.

-- 
Sent from Kaiten Mail. Please excuse my brevity.

Re: [ccp4bb] metals disapear

[Dean Derbyshire]

and others..



Wow what a response, seems I started several discussions too.

Good to see the experts views, thanks.



I will try and respond individually but for now a bit background (many 
questions asking for details and suggesting similar things done already - glad 
to see I've been on the right track).



So project 'x' (teehee) has an active site with 2 metals, supposed to be 
di-zinc but XRF anaysis (and sample colour) suggest a mix... mostly iron and 
zinc. Seems the protein is quite promiscuous and scavanges any metal around 
during production.. Of cours ethat has opened adifferent debate with regards 
'native' states.

Have managed to produce spliting rod/needles at neutral pH (I had the notion 
that lower pHs may be an issue, for a related protein I have structures from 
crystals grown at pHs 5-6.5 and as mentioned by Ronny at 5 metals were never 
there).  Data colledctions have been done using a helical strategy with data 
quality lasting throughout collection (approx 2.3Å) .  An XRF scan directly 
after the last point already demonstrated that metals have vanished.

One complication: crystals are often not simply split but are intergrown with 
the ends having diffeent cell parameters, but thats a different problem :0)



One suggestion that I had not thought of, and will... is move away from the 
absorption edge (thanks Klaus).  Funny normaly one wants the anom signal and it 
sort of goes against the grain to collect where you essentially minimise it, 
but makes absolute sense in this case.

I will also try a much reduced dose regime.. get a modest (but complete) 
structure... qu.  is hard and fast better than low dose and slow?



Anyway thaks for all the comments... nice to hear from names from my past too - 
hi, hope all is well.

:0)

D.




From: Helland Ronny [ronny.hell...@uit.no]
Sent: 01 May 2014 23:57
To: Dean Derbyshire
Subject: RE: metals disapear

Hi Dean,

What is the metal and what is the pH where you crystallized your protein? We 
had a Mg binding protein (DNA binding protein) which crystallized both at at pH 
5 and pH 7. At pH 7 the Mg was there, at pH 5 it was not. Although the 
conditions were slightly different, we suspected  that the acidic groups 
binding the metal might be protonated at pH 5 thus reducing the affinity for 
the metal. We never tested this further so it is still only speculations.

Regards,
Ronny

***
Ronny Helland
Department of Chemistry, NorStruct
Research Park 3
Faculty of Science and Technology
UiT – The Arctic University of Norway
9037 Tromsø
Norway

Mail: ronny.hell...@uit.no
Phone: +47 77646474

From: CCP4 bulletin board [mailto:CCP4BB@JISCMAIL.AC.UK] On Behalf Of Dean 
Derbyshire
Sent: 30. april 2014 12:33
To: CCP4BB@JISCMAIL.AC.UK
Subject: [ccp4bb] metals disapear

Hi all,
Has anyone experienced catalytic metal ions disappearing during data collection 
?
If so, is there a way of preventing it?
D.

   Dean Derbyshire
   Senior Research Scientist
[cid:image001.jpg@01CF6598.8312B770]
   Box 1086
   SE-141 22 Huddinge
   SWEDEN
   Visit: Lunastigen 7
   Direct: +46 8 54683219
   www.medivir.com

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exempt from disclosure under applicable law. If you are not the intended 
recipient, please be notified that any dissemination, distribution or copying 
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notify us immediately.
Thank you for your cooperation.

Re: [ccp4bb] verifying protein crystal content by mass spectrometry or SDS-PAGE

[Bert Van-Den-Berg]

In principle this is straightforward, but you'll need reasonably-sized 
crystals. You'll have to wash them very well in mother liquor (protein buffer 
will probably dissolve the crystals). I do at least 3 serial transfers in large 
(5-10 ul) drops (with a loop), and for each transfer I  move the crystals 
around with a clean loop for a few seconds to get rid of the crystallization 
solution (containing soluble protein). Don't worry about crystals 
cracking/breaking during washing. When the crystals are clean I just pipette 
them up with some mother liquor and add SDS PAGE sample buffer and run them out 
on gel as normal. You can run out the rest of the mother liquor in the last 
wash drop as a control (to see if you got rid of all the soluble protein). If 
the crystal habit is the same, combining crystals from slightly different 
conditions should be ok.
Things get more complicated if you have small crystals or crystals embedded in 
skin (protein in the skin is not necessarily the same as in the crystals). 
Precipitation is mostly ok because you can get rid of it during the washing 
step.
In terms of quantities, if you assume a protein concentration in the crystal of 
~500 mg/ml, then a cube of 100 micron (= large crystal) contains ~0.5 microgram 
(1 nl) protein. So if two of your crystal dimensions are very small (needles) 
you'll end up with very little protein per crystal. Also, for each small 
crystal you wash you'll introduce a relatively large amount of soluble protein 
from the drop. If you have needle clusters it could work, if you can 
transfer/wash the entire cluster.

HTH, Bert

From: CCP4 bulletin board [CCP4BB@JISCMAIL.AC.UK] on behalf of sreetama das 
[somon_...@yahoo.co.in]
Sent: Friday, May 02, 2014 9:58 AM
To: CCP4BB@JISCMAIL.AC.UK
Subject: [ccp4bb] verifying protein crystal content by mass spectrometry or 
SDS-PAGE

Dear All,
   Is there any protocol for preparing a sample from 
(cleaning/dissolving) protein crystals for verifying their mass through mass 
spectrometry or SDS-PAGE? How many protein crystals are required? Should they 
all be from the same well, or can they be from different wells with slight 
changes in protein concentration/precipitant concentration/ pH? Should the 
crystals be cleaned with the reservoir solution and then dissolved in the 
protein buffer?

I am getting very thin, needle-like crystals which are too tiny for mounting. 
Adding Izit dye has also not been conclusive. Similar looking crystals have 
appeared in 3 conditions. Changing precipitant concentration, protein 
concentration, pH , and seeding have made no difference so far. I wish to 
determine whether the full protein is crystallizing, or only some fragment. The 
protein molecular weight is ~22KDa, and the crystals take ~3 weeks to grow.

Thanks in advance,
sreetama

[ccp4bb] Crystals Disappearing Overnight

[dusky dew]

Dear All,

I am trying to crystallize a protein with Adenosine.  My protein is in 20
mM Tris, 300 mM NaCl and the crystals appear in a condition with 5 percent
PEG8K, 0.1 M Sodium Cacodylate.  The protein is incubated with adenosine
for 1/2 hr before setting the drop.  The crystals appear right after the
drop is set but unfortunately they dissolve overnight.  The plate is kept
at 16 degree.

Could anyone elaborate on this.  Is it possibly occurring because Adenosine
has stability issues.

Thanks for your suggestions.
~ Maria

Re: [ccp4bb] Crystals Disappearing Overnight

[Tim Gruene]

-BEGIN PGP SIGNED MESSAGE-
Hash: SHA1

Dear Maria,

this is similar to the condition I used for my PhD thesis. I suppose
the following happens:

when you mix the drop the protein crystallises by inverse salting-in
because you dilute the high-salt concentration. This happens
instantaneously and you are lucky enough to observe crystals.

As you leave the drop overnight you are observing the opposite from
what normally happens: your drop gets larger instead of smaller
because the hygroscopy of the 150mM NaCl is stronger than that of 2.5%
PEG8K and you further dilute the drop so that the crystal disappears.

Check if your drops get bigger overnight to check if my assumption is
correct.

During my PhD I worked with 0.5M NaCl and maybe I am wrong that 150mM
NaCl is stronger than 2.5% PEG8k.

Best,
Tim

On 05/02/2014 01:39 PM, dusky dew wrote:
> Dear All,
> 
> I am trying to crystallize a protein with Adenosine.  My protein is
> in 20 mM Tris, 300 mM NaCl and the crystals appear in a condition
> with 5 percent PEG8K, 0.1 M Sodium Cacodylate.  The protein is
> incubated with adenosine for 1/2 hr before setting the drop.  The
> crystals appear right after the drop is set but unfortunately they
> dissolve overnight.  The plate is kept at 16 degree.
> 
> Could anyone elaborate on this.  Is it possibly occurring because
> Adenosine has stability issues.
> 
> Thanks for your suggestions. ~ Maria
> 

- -- 
- --
Dr Tim Gruene
Institut fuer anorganische Chemie
Tammannstr. 4
D-37077 Goettingen

GPG Key ID = A46BEE1A

-BEGIN PGP SIGNATURE-
Version: GnuPG v1.4.12 (GNU/Linux)
Comment: Using GnuPG with Icedove - http://www.enigmail.net/

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=LbR6
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Re: [ccp4bb] Crystals Disappearing Overnight

[Matthew BOWLER]

Dear Tim,
you are right that 150mM NaCl is 'stronger' than 2.5% PEG.  If you 
calculate the relative humidity difference between 150 and 300mM Nacl 
you get 99.5 vs 98.9% whereas the difference between 5 and 2.5% P8K is 
99.96 vs 99.99% ie virtually nothing.  You can calculate these values 
here: http://go.esrf.eu/RH.


Cheers, Matt.



On 2014-05-02 13:56, Tim Gruene wrote:

-BEGIN PGP SIGNED MESSAGE-
Hash: SHA1

Dear Maria,

this is similar to the condition I used for my PhD thesis. I suppose
the following happens:

when you mix the drop the protein crystallises by inverse salting-in
because you dilute the high-salt concentration. This happens
instantaneously and you are lucky enough to observe crystals.

As you leave the drop overnight you are observing the opposite from
what normally happens: your drop gets larger instead of smaller
because the hygroscopy of the 150mM NaCl is stronger than that of 
2.5%

PEG8K and you further dilute the drop so that the crystal disappears.

Check if your drops get bigger overnight to check if my assumption is
correct.

During my PhD I worked with 0.5M NaCl and maybe I am wrong that 150mM
NaCl is stronger than 2.5% PEG8k.

Best,
Tim

On 05/02/2014 01:39 PM, dusky dew wrote:

Dear All,

I am trying to crystallize a protein with Adenosine.  My protein is
in 20 mM Tris, 300 mM NaCl and the crystals appear in a condition
with 5 percent PEG8K, 0.1 M Sodium Cacodylate.  The protein is
incubated with adenosine for 1/2 hr before setting the drop.  The
crystals appear right after the drop is set but unfortunately they
dissolve overnight.  The plate is kept at 16 degree.

Could anyone elaborate on this.  Is it possibly occurring because
Adenosine has stability issues.

Thanks for your suggestions. ~ Maria



- --
- --
Dr Tim Gruene
Institut fuer anorganische Chemie
Tammannstr. 4
D-37077 Goettingen

GPG Key ID = A46BEE1A

-BEGIN PGP SIGNATURE-
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Comment: Using GnuPG with Icedove - http://www.enigmail.net/

iD8DBQFTY4gDUxlJ7aRr7hoRAvZcAJ9fnqKmsjWvsvQifgB2oG3EH4/h9wCghJVA
9Ng4dZzXQG5+LQiPwZVdXXQ=
=LbR6
-END PGP SIGNATURE-


--
Matthew Bowler
Synchrotron Science Group
European Molecular Biology Laboratory
BP 181, 6 rue Jules Horowitz
38042 Grenoble Cedex 9
France
===
Tel: +33 (0) 4.76.20.76.37
Fax: +33 (0) 4.76.88.29.04

http://www.embl.fr/
===

Re: [ccp4bb] Confusion about space group nomenclature

[Jim Pflugrath]

After all this discussion, I think that Bernhard can now lay the claim that 
these 65 space groups should really just be labelled the "Rupp" space groups.  
At least it is one word.

Jim


From: CCP4 bulletin board [CCP4BB@JISCMAIL.AC.UK] on behalf of Bernhard Rupp 
[hofkristall...@gmail.com]
Sent: Friday, May 02, 2014 3:04 AM
To: CCP4BB@JISCMAIL.AC.UK
Subject: Re: [ccp4bb] Confusion about space group nomenclature
….

Enough of this thread.

Over and out, BR

[ccp4bb] Job vacancy: software engineer

[Gary Battle]

We are seeking a motivated Software Engineer to join the Protein Data 
Bank in Europe team at the European Bioinformatics Institute located on 
the Wellcome Trust Genome Campus near Cambridge in the UK.


Together with our international partner organizations, PDBe accepts and 
curates depositions of 3D structural data for the global archives (PDB 
and EMDB). Deposition and curation are carried out with a unified 
software system developed jointly by the wwPDB partners in Europe, the 
US and Japan. PDBe develops and maintains a number of key components of 
this software system, including the deposition user-interface, the 
workflow system and a number of structure-validation software pipelines.


We now have an opening for a software engineer to maintain and develop 
these components, and to help with general systems-administration tasks 
required to keep the system up and running at PDBe. These components are 
part of a web application implemented in Python using the Django 
framework for model-view-controller (MVC) functionality, which makes 
extensive use of Ajax/Javascript for web front-end functionality.


For more information and to apply, visit: http://bit.ly/1kAKXXt

--
Gary Battle
Protein Data Bank in Europe (PDBe)
EMBL-EBI

http://www.facebook.com/proteindatabank
http://twitter.com/PDBeurope

Re: [ccp4bb] Confusion about space group nomenclature

[Keller, Jacob]

Or "space gRupps?"

From: CCP4 bulletin board [mailto:CCP4BB@JISCMAIL.AC.UK] On Behalf Of Jim 
Pflugrath
Sent: Friday, May 02, 2014 8:36 AM
To: CCP4BB@JISCMAIL.AC.UK
Subject: Re: [ccp4bb] Confusion about space group nomenclature

After all this discussion, I think that Bernhard can now lay the claim that 
these 65 space groups should really just be labelled the "Rupp" space groups.  
At least it is one word.

Jim


From: CCP4 bulletin board [CCP4BB@JISCMAIL.AC.UK] on behalf of Bernhard Rupp 
[hofkristall...@gmail.com]
Sent: Friday, May 02, 2014 3:04 AM
To: CCP4BB@JISCMAIL.AC.UK
Subject: Re: [ccp4bb] Confusion about space group nomenclature


Enough of this thread.

Over and out, BR

[ccp4bb] Sep. 17-20, Hamburg - Crystallization for novel radiation sources - ICCBM15

[mesters]

Exciting program featuring many highly-esteemed colleagues from all over 
the world (http://www.iccbm15.org).


*Early abstract submission deadline May 16th if to be considered for an 
oral presentation*,
last possible submission date is July 31th, if to be included in the 
Abstract book.


*15th International Conference on the Crystallization of Biological 
Macromolecules **

*
Focus on crystallization for novel radiation sources and use of 
complementary methods (such as CryoEM)


The conference is preceded by a hands-on crystallization workshop (Sep. 
14-16)


Chairpersons: Christian Betzel and Jeroen Mesters

[ccp4bb] migration from monitor to wall mounted screen and projector

[Oganesyan, Vaheh]

Hi all,

I'm planning migration from CRT monitor to wall mounted screen with projector 
that will support stereo. Mid-range emitter like AE125 for small office (4m by 
4m) like mine is sufficient. I'm looking for advise on projector and screen. It 
looks like ViewSonic PJD7820HD ($699) with native (at least 1280 x 1024 at 120 
Hz) support should work.
Have any of you tried this? What are other options for projector and are there 
preferences for wall mount screens?

Thank you.

Regards,

Vaheh Oganesyan
MedImmune, ADPE
www.medimmune.com

To the extent this electronic communication or any of its attachments contain 
information that is not in the public domain, such information is considered by 
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be read and/or used only by the individual(s) for whom it is intended. If you 
have received this electronic communication in error, please reply to the 
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and any accompanying documents from your system immediately, without copying, 
reviewing or otherwise using them for any purpose. Thank you for your 
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attachments contain information that is not in the public domain, such 
information is considered by MedImmune to be confidential and proprietary. This 
communication is expected to be read and/or used only by the individual(s) for 
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error, please reply to the sender advising of the error in transmission and 
delete the original message and any accompanying documents from your system 
immediately, without copying, reviewing or otherwise using them for any 
purpose. Thank you for your cooperation.

Re: [ccp4bb] Confusion about space group nomenclature

[Bernhard Rupp]

You guys are enantioqueer.

BR

 

From: CCP4 bulletin board [mailto:CCP4BB@JISCMAIL.AC.UK] On Behalf Of
Keller, Jacob
Sent: Freitag, 2. Mai 2014 15:43
To: CCP4BB@JISCMAIL.AC.UK
Subject: Re: [ccp4bb] Confusion about space group nomenclature

 

Or "space gRupps?"

 

From: CCP4 bulletin board [mailto:CCP4BB@JISCMAIL.AC.UK] On Behalf Of Jim
Pflugrath
Sent: Friday, May 02, 2014 8:36 AM
To: CCP4BB@JISCMAIL.AC.UK
Subject: Re: [ccp4bb] Confusion about space group nomenclature

 

After all this discussion, I think that Bernhard can now lay the claim that
these 65 space groups should really just be labelled the "Rupp" space
groups.  At least it is one word. 

 

Jim

 

  _  

From: CCP4 bulletin board [CCP4BB@JISCMAIL.AC.UK] on behalf of Bernhard Rupp
[hofkristall...@gmail.com]
Sent: Friday, May 02, 2014 3:04 AM
To: CCP4BB@JISCMAIL.AC.UK
Subject: Re: [ccp4bb] Confusion about space group nomenclature
..

 

Enough of this thread.

 

Over and out, BR

 

 

 

Re: [ccp4bb] Confusion about space group nomenclature

[Bernhard Rupp]

I actually meant enantioweird.

 

From: CCP4 bulletin board [mailto:CCP4BB@JISCMAIL.AC.UK] On Behalf Of
Keller, Jacob
Sent: Freitag, 2. Mai 2014 15:43
To: CCP4BB@JISCMAIL.AC.UK
Subject: Re: [ccp4bb] Confusion about space group nomenclature

 

Or "space gRupps?"

 

From: CCP4 bulletin board [mailto:CCP4BB@JISCMAIL.AC.UK] On Behalf Of Jim
Pflugrath
Sent: Friday, May 02, 2014 8:36 AM
To: CCP4BB@JISCMAIL.AC.UK
Subject: Re: [ccp4bb] Confusion about space group nomenclature

 

After all this discussion, I think that Bernhard can now lay the claim that
these 65 space groups should really just be labelled the "Rupp" space
groups.  At least it is one word. 

 

Jim

 

  _  

From: CCP4 bulletin board [CCP4BB@JISCMAIL.AC.UK] on behalf of Bernhard Rupp
[hofkristall...@gmail.com]
Sent: Friday, May 02, 2014 3:04 AM
To: CCP4BB@JISCMAIL.AC.UK
Subject: Re: [ccp4bb] Confusion about space group nomenclature
..

 

Enough of this thread.

 

Over and out, BR

 

 

 

Re: [ccp4bb] Crystals Disappearing Overnight

[Matthew Franklin]

Hi Maria -

I think you already have a likely answer, but here's another one which I 
have observed many times:


Temperature differences.  If your crystallization plate is moved from 
one temperature to another (lab vs. crystal incubator), or even if it's 
left on the bench but the lab temperature varies overnight, you can get 
a temperature difference between your reservoir solution and the rest of 
the crystallization chamber. This can cause water condensation on the 
cover slip, which will dilute a hanging drop (and even a sitting drop if 
it's high enough up) and cause things to dissolve.


The solution to this one is just careful control of the crystal plate 
environment.  The same is true after the crystals are done growing - you 
can lose an entire drop of nice crystals from taking the plate out of 
the incubator to look at it under the microscope!


Hope that helps,
Matt


On 5/2/14 7:39 AM, dusky dew wrote:

Dear All,

I am trying to crystallize a protein with Adenosine.  My protein is in 
20 mM Tris, 300 mM NaCl and the crystals appear in a condition with 5 
percent PEG8K, 0.1 M Sodium Cacodylate.  The protein is incubated with 
adenosine for 1/2 hr before setting the drop.  The crystals appear 
right after the drop is set but unfortunately they dissolve overnight. 
 The plate is kept at 16 degree.


Could anyone elaborate on this.  Is it possibly occurring because 
Adenosine has stability issues.


Thanks for your suggestions.
~ Maria





--
Matthew Franklin, Ph. D.
Senior Scientist
New York Structural Biology Center
89 Convent Avenue, New York, NY 10027
(212) 939-0660 ext. 9374

Re: [ccp4bb] Confusion about space group nomenclature

[Gerard Bricogne]

Dear all,

 It is nice to see this rather high-brow thread end with some verbal
humour, but I think the subject might deserve a better treatment than it has
received. Three-dimensional crystallographic space groups were classified by
3 different people as far back as the 19th century, and questions such as
those that have been discussed are ultra-classical in group theory - so if
this thread is to lead us towards the spool rather than the ragged end, we
should look towards those sources.

 It has perhaps been an unfortunate side effect of the creation of the
International Tables that we have tended to consider such topics as being
part of our private microcosm and folklore, all compiled between the covers
of a single book. Perhaps we should be a little less flippant: if we are to
identify the actual "ultimate authorities" on this topic, we may have to
look further than colleagues who can be contacted by e-mail and come up with
an answer within a day.


 Happy weekend to all,
 
   Gerard.

--
On Fri, May 02, 2014 at 01:42:36PM +, Keller, Jacob wrote:
> Or "space gRupps?"
> 
> From: CCP4 bulletin board [mailto:CCP4BB@JISCMAIL.AC.UK] On Behalf Of Jim 
> Pflugrath
> Sent: Friday, May 02, 2014 8:36 AM
> To: CCP4BB@JISCMAIL.AC.UK
> Subject: Re: [ccp4bb] Confusion about space group nomenclature
> 
> After all this discussion, I think that Bernhard can now lay the claim that 
> these 65 space groups should really just be labelled the "Rupp" space groups. 
>  At least it is one word.
> 
> Jim
> 
> 
> From: CCP4 bulletin board [CCP4BB@JISCMAIL.AC.UK] on behalf of Bernhard Rupp 
> [hofkristall...@gmail.com]
> Sent: Friday, May 02, 2014 3:04 AM
> To: CCP4BB@JISCMAIL.AC.UK
> Subject: Re: [ccp4bb] Confusion about space group nomenclature
> 
> 
> Enough of this thread.
> 
> Over and out, BR

[ccp4bb] How to get a CIF configure for a designed ligand

[Robert]

 Dear all,
  Thank all of you for helping me. And my problem is solved.

Robert.

Re: [ccp4bb] Confusion about space group nomenclature

[George Sheldrick]

In my program documentation I usually call these 65 the Sohnke space 
groups, as defined by the IUCr:

http://reference.iucr.org/dictionary/Sohnke_groups

George


On 05/02/2014 02:35 PM, Jim Pflugrath wrote:
After all this discussion, I think that Bernhard can now lay the claim 
that these 65 space groups should really just be labelled the "Rupp" 
space groups.  At least it is one word.


Jim


*From:* CCP4 bulletin board [CCP4BB@JISCMAIL.AC.UK] on behalf of 
Bernhard Rupp [hofkristall...@gmail.com]

*Sent:* Friday, May 02, 2014 3:04 AM
*To:* CCP4BB@JISCMAIL.AC.UK
*Subject:* Re: [ccp4bb] Confusion about space group nomenclature
….

Enough of this thread.

Over and out, BR




--
Prof. George M. Sheldrick FRS
Dept. Structural Chemistry,
University of Goettingen,
Tammannstr. 4,
D37077 Goettingen, Germany
Tel. +49-551-39-33021 or -33068
Fax. +49-551-39-22582

Re: [ccp4bb] Confusion about space group nomenclature

[Ronald E Stenkamp]

I agree with George.  Sohnke is only six letters and it's been used for a long 
time to label these groups.  Ron

On Fri, 2 May 2014, George Sheldrick wrote:


In my program documentation I usually call these 65 the Sohnke space groups,
as defined by the IUCr:
http://reference.iucr.org/dictionary/Sohnke_groups 

George


On 05/02/2014 02:35 PM, Jim Pflugrath wrote:
  After all this discussion, I think that Bernhard can now lay the
  claim that these 65 space groups should really just be labelled
  the "Rupp" space groups.  At least it is one word.
Jim

__
From: CCP4 bulletin board [CCP4BB@JISCMAIL.AC.UK] on behalf of Bernhard
Rupp [hofkristall...@gmail.com]
Sent: Friday, May 02, 2014 3:04 AM
To: CCP4BB@JISCMAIL.AC.UK
Subject: Re: [ccp4bb] Confusion about space group nomenclature
….

 

Enough of this thread.

 

Over and out, BR

 

 

 



--
Prof. George M. Sheldrick FRS
Dept. Structural Chemistry, 
University of Goettingen,

Tammannstr. 4,
D37077 Goettingen, Germany
Tel. +49-551-39-33021 or -33068
Fax. +49-551-39-22582

Re: [ccp4bb] Confusion about space group nomenclature

[Jrh Gmail]

Dear George
My student class would not find that IUCr dictionary definition helpful. What 
they do find helpful is to state that they cannot contain an inversion or a 
mirror. 
To honour Sohnke is one thing but is it really necessary as a label? You're 
from Huddersfield I am from Wakefield ie let's call a spade a spade (not a 
'Black and Decker'). 
Cheers
John

Prof John R Helliwell DSc

> On 2 May 2014, at 17:01, George Sheldrick  
> wrote:
> 
> In my program documentation I usually call these 65 the Sohnke space groups, 
> as defined by the IUCr: 
> http://reference.iucr.org/dictionary/Sohnke_groups  
> 
> George
> 
> 
>> On 05/02/2014 02:35 PM, Jim Pflugrath wrote:
>> After all this discussion, I think that Bernhard can now lay the claim that 
>> these 65 space groups should really just be labelled the "Rupp" space 
>> groups.  At least it is one word. 
>> 
>> Jim
>> 
>> From: CCP4 bulletin board [CCP4BB@JISCMAIL.AC.UK] on behalf of Bernhard Rupp 
>> [hofkristall...@gmail.com]
>> Sent: Friday, May 02, 2014 3:04 AM
>> To: CCP4BB@JISCMAIL.AC.UK
>> Subject: Re: [ccp4bb] Confusion about space group nomenclature
>> ….
>>  
>> Enough of this thread.
>>  
>> Over and out, BR
> 
> 
> -- 
> Prof. George M. Sheldrick FRS
> Dept. Structural Chemistry, 
> University of Goettingen,
> Tammannstr. 4,
> D37077 Goettingen, Germany
> Tel. +49-551-39-33021 or -33068
> Fax. +49-551-39-22582
> 

Re: [ccp4bb] Confusion about space group nomenclature

[Bernard D Santarsiero]

It well-known in the mathematics community to refer to these as Sohnke groups, 
or even Jordan-Sohnke groups.  Camille Jordan identified them in 1868-1869, and 
L. A. Sohnke in 1879.  William Barlow derived all 230 space groups by adding 
reflection operations to Sohnke's 65 groups in 1894-1989.


On May 2, 2014, at 11:42 AM, Jrh Gmail wrote:

> Dear George
> My student class would not find that IUCr dictionary definition helpful. What 
> they do find helpful is to state that they cannot contain an inversion or a 
> mirror. 
> To honour Sohnke is one thing but is it really necessary as a label? You're 
> from Huddersfield I am from Wakefield ie let's call a spade a spade (not a 
> 'Black and Decker'). 
> Cheers
> John
> 
> Prof John R Helliwell DSc
> 
> On 2 May 2014, at 17:01, George Sheldrick  
> wrote:
> 
>> In my program documentation I usually call these 65 the Sohnke space groups, 
>> as defined by the IUCr: 
>> http://reference.iucr.org/dictionary/Sohnke_groups  
>> 
>> George
>> 

Re: [ccp4bb] Confusion about space group nomenclature

[Gerard Bricogne]

Dear John,

 What is wrong with honouring Sohnke by using his name for something
that he first saw a point in defining, and in investigating the properties
resulting from that definition? Why insist that we should instead replace
his name by an adjective or a circumlocution? What would we say if someone
outside our field asked us not to talk about a Bragg reflection, or the
Ewald sphere, or the Laue method, but to use instead some clever adjective
or a noun-phrase as long as the name of a Welsh village to explain what
these mean? 

 Again, I think we should have a bit more respect here. When there are
simple adjectives to describe a mathematical properties, the mathematical
vocabulary uses it (like a "normal" subgroup). However, when someone has
seen that a definition by a conjunction of properties (i.e. something
describable by a sentence) turns out to characterise objects that have much
more interesting properties than just those by which they were defined, then
they are often called by the name of the mathematician who first saw that
there is more to them than what defines them. Examples: Coxeter groups, or
Lie algebras, or the Leech lattice, or the Galois group of a field, the
Cayley tree of a group ... . It is the name of the first witness to a
mathematical phenomenon, just as we call chemical reactions by the name of
the chemist who saw that mixing certain chemicals together led not just to a
mixture of those chemicals.

 So why don't we give Sohnke what belongs to him, just as we expect
other scientists to give to Laue, Bragg and Ewald what we think belongs to
them? Maybe students would not be as refractory to the idea as might first
be thought.


 With best wishes,
 
  Gerard.

--
On Fri, May 02, 2014 at 05:42:34PM +0100, Jrh Gmail wrote:
> Dear George
> My student class would not find that IUCr dictionary definition helpful. What 
> they do find helpful is to state that they cannot contain an inversion or a 
> mirror. 
> To honour Sohnke is one thing but is it really necessary as a label? You're 
> from Huddersfield I am from Wakefield ie let's call a spade a spade (not a 
> 'Black and Decker'). 
> Cheers
> John
> 
> Prof John R Helliwell DSc
> 
> > On 2 May 2014, at 17:01, George Sheldrick  
> > wrote:
> > 
> > In my program documentation I usually call these 65 the Sohnke space 
> > groups, as defined by the IUCr: 
> > http://reference.iucr.org/dictionary/Sohnke_groups  
> > 
> > George
> > 
> > 
> >> On 05/02/2014 02:35 PM, Jim Pflugrath wrote:
> >> After all this discussion, I think that Bernhard can now lay the claim 
> >> that these 65 space groups should really just be labelled the "Rupp" space 
> >> groups.  At least it is one word. 
> >> 
> >> Jim
> >> 
> >> From: CCP4 bulletin board [CCP4BB@JISCMAIL.AC.UK] on behalf of Bernhard 
> >> Rupp [hofkristall...@gmail.com]
> >> Sent: Friday, May 02, 2014 3:04 AM
> >> To: CCP4BB@JISCMAIL.AC.UK
> >> Subject: Re: [ccp4bb] Confusion about space group nomenclature
> >> ….
> >>  
> >> Enough of this thread.
> >>  
> >> Over and out, BR
> > 
> > 
> > -- 
> > Prof. George M. Sheldrick FRS
> > Dept. Structural Chemistry, 
> > University of Goettingen,
> > Tammannstr. 4,
> > D37077 Goettingen, Germany
> > Tel. +49-551-39-33021 or -33068
> > Fax. +49-551-39-22582

Re: [ccp4bb] Confusion about space group nomenclature

[Jens Kaiser]

Bernhard et al,

> 
> 
> @ Jens:
> 
> > I think the precise and correct term applicable to the "65" should
> be pro-chiral spacegroups. They are not chiral by themselves, but
> addition of "something" /allows/ for the creation of a chiral object
> (i.e. the crystal).
> 
> For a moment I though we have it…. but then the rest would be
> anti-chiral? 

I never thought about it that way but actually, yes! You put something
chiral into their AU and those little buggers go on and invert it. They
are really anti-chiral. So we have the three groups chiral, prochiral
and antichiral.

I like the suggestion of calling the chiral and prochiral groups the
Sohncke groups (beware everybody misspelled that poor guy, he has a ck
in his last name). That keeps the history of our field in the
expressions we use and might even inspire people to look up who the
people were on whose shoulders we stand.

Jens

PS: I had to laugh when I looked him up on Wikipedia: "Leonhard Sohncke
(22 February 1842 Halle – 1 November 1897 München) was a German
mathematician who classified the 65 chiral space groups, sometimes
called Sohncke groups." The German Wikipedia entry is much more
complete. 
  Also, I guess inspired by this thread, "anonymous" created an entry in
Wikipedia "L.A. Sonke" - about 3h ago...

Re: [ccp4bb] Confusion about space group nomenclature

[Gerard Bricogne]

Dear Jens,

 I hope I can make a couple more remarks, and then I will keep quiet.
 
 The first is that your suggestion that we do use Sohncke's name in
relation to these groups may still leave the impression that, as John put it
earlier, this name is just a "label". This is where I want to point out what
it is exactly that we owe Sohncke. It is not the bland definition of a list
of groups of Euclidean transformations with certain properties, printed in
some section of IT-A: it is a classification result, namely that if you look
for all the groups with those properties, there are only 65 types of them,
and here they are. So it is in that "65", that we take for granted because
we read it in the ITs, that Sohncke's contribution lies. 

 A second remark is about wanting to find where the attribute of
chirality (or pro-chirality) resides. As was pointed out, it is not the
groups themselves that have these attributes: it is objects in space on
which the groups act. A sensible adjective might therefore exist to
designate the 65, namely "chirality-preserving".


 With best wishes,
 
  Gerard.

--
On Fri, May 02, 2014 at 12:36:59PM -0700, Jens Kaiser wrote:
> Bernhard et al,
> 
> > 
> > 
> > @ Jens:
> > 
> > > I think the precise and correct term applicable to the "65" should
> > be pro-chiral spacegroups. They are not chiral by themselves, but
> > addition of "something" /allows/ for the creation of a chiral object
> > (i.e. the crystal).
> > 
> > For a moment I though we have it…. but then the rest would be
> > anti-chiral? 
> 
> I never thought about it that way but actually, yes! You put something
> chiral into their AU and those little buggers go on and invert it. They
> are really anti-chiral. So we have the three groups chiral, prochiral
> and antichiral.
> 
> I like the suggestion of calling the chiral and prochiral groups the
> Sohncke groups (beware everybody misspelled that poor guy, he has a ck
> in his last name). That keeps the history of our field in the
> expressions we use and might even inspire people to look up who the
> people were on whose shoulders we stand.
> 
> Jens
> 
> PS: I had to laugh when I looked him up on Wikipedia: "Leonhard Sohncke
> (22 February 1842 Halle – 1 November 1897 München) was a German
> mathematician who classified the 65 chiral space groups, sometimes
> called Sohncke groups." The German Wikipedia entry is much more
> complete. 
>   Also, I guess inspired by this thread, "anonymous" created an entry in
> Wikipedia "L.A. Sonke" - about 3h ago...

Re: [ccp4bb] Confusion about space group nomenclature

[Jrh Gmail]

Dear Gerard
I am duly reprimanded .
You are quite correct .
Have a good weekend
John

Prof John R Helliwell DSc

> On 2 May 2014, at 18:16, Gerard Bricogne  wrote:
> 
> Dear John,
> 
> What is wrong with honouring Sohnke by using his name for something
> that he first saw a point in defining, and in investigating the properties
> resulting from that definition? Why insist that we should instead replace
> his name by an adjective or a circumlocution? What would we say if someone
> outside our field asked us not to talk about a Bragg reflection, or the
> Ewald sphere, or the Laue method, but to use instead some clever adjective
> or a noun-phrase as long as the name of a Welsh village to explain what
> these mean? 
> 
> Again, I think we should have a bit more respect here. When there are
> simple adjectives to describe a mathematical properties, the mathematical
> vocabulary uses it (like a "normal" subgroup). However, when someone has
> seen that a definition by a conjunction of properties (i.e. something
> describable by a sentence) turns out to characterise objects that have much
> more interesting properties than just those by which they were defined, then
> they are often called by the name of the mathematician who first saw that
> there is more to them than what defines them. Examples: Coxeter groups, or
> Lie algebras, or the Leech lattice, or the Galois group of a field, the
> Cayley tree of a group ... . It is the name of the first witness to a
> mathematical phenomenon, just as we call chemical reactions by the name of
> the chemist who saw that mixing certain chemicals together led not just to a
> mixture of those chemicals.
> 
> So why don't we give Sohnke what belongs to him, just as we expect
> other scientists to give to Laue, Bragg and Ewald what we think belongs to
> them? Maybe students would not be as refractory to the idea as might first
> be thought.
> 
> 
> With best wishes,
> 
>  Gerard.
> 
> --
>> On Fri, May 02, 2014 at 05:42:34PM +0100, Jrh Gmail wrote:
>> Dear George
>> My student class would not find that IUCr dictionary definition helpful. 
>> What they do find helpful is to state that they cannot contain an inversion 
>> or a mirror. 
>> To honour Sohnke is one thing but is it really necessary as a label? You're 
>> from Huddersfield I am from Wakefield ie let's call a spade a spade (not a 
>> 'Black and Decker'). 
>> Cheers
>> John
>> 
>> Prof John R Helliwell DSc
>> 
>>> On 2 May 2014, at 17:01, George Sheldrick  
>>> wrote:
>>> 
>>> In my program documentation I usually call these 65 the Sohnke space 
>>> groups, as defined by the IUCr: 
>>> http://reference.iucr.org/dictionary/Sohnke_groups  
>>> 
>>> George
>>> 
>>> 
 On 05/02/2014 02:35 PM, Jim Pflugrath wrote:
 After all this discussion, I think that Bernhard can now lay the claim 
 that these 65 space groups should really just be labelled the "Rupp" space 
 groups.  At least it is one word. 
 
 Jim
 
 From: CCP4 bulletin board [CCP4BB@JISCMAIL.AC.UK] on behalf of Bernhard 
 Rupp [hofkristall...@gmail.com]
 Sent: Friday, May 02, 2014 3:04 AM
 To: CCP4BB@JISCMAIL.AC.UK
 Subject: Re: [ccp4bb] Confusion about space group nomenclature
 ….
 
 Enough of this thread.
 
 Over and out, BR
>>> 
>>> 
>>> -- 
>>> Prof. George M. Sheldrick FRS
>>> Dept. Structural Chemistry, 
>>> University of Goettingen,
>>> Tammannstr. 4,
>>> D37077 Goettingen, Germany
>>> Tel. +49-551-39-33021 or -33068
>>> Fax. +49-551-39-22582

Re: [ccp4bb] Confusion about space group nomenclature

[Bernhard Rupp]

Fellows,

my apologies for having sparked that space war.
I wish to interject than in my earlier postings to this thread
to Howard I did give credit to the '65 sons of Sohnke' (albeit sans c). 

If we honor him, we ought to spell him right.
http://reference.iucr.org/dictionary/Sohnke_groups
Sohnke (IUCr)
Sohncke (same page, IUCr)
Sohncke (Wikipedia and German primary sources):
http://www.deutsche-biographie.de/sfz80497.html

Ron posted the Sohncke link to me off-line right away and I admit that I 
realized the same by googling 
'chiral space groups' which immediately leads you to Wikipedia's space group 
and Sohncke 
entry. It also shows (in addition to an interesting 74-group page...) my own 
web list, which imho 
erroneously used the improper (no pun intended) adjective 'chiral' for the 65 
Sohncke groups. No more.

Nonetheless, this does not necessarily discredit my quest for a descriptive 
adjective, and the
absence of such after this lively engagement might indicate that the question 
was not quite as 
illegitimate as it might have appeared even to the cognoscenti at first sight. 
Nonetheless,

a toast to Sohncke!

BR 


-Original Message-
From: CCP4 bulletin board [mailto:CCP4BB@JISCMAIL.AC.UK] On Behalf Of Gerard 
Bricogne
Sent: Friday, May 02, 2014 7:17 PM
To: CCP4BB@JISCMAIL.AC.UK
Subject: Re: [ccp4bb] Confusion about space group nomenclature

Dear John,

 What is wrong with honouring Sohnke by using his name for something that 
he first saw a point in defining, and in investigating the properties resulting 
from that definition? Why insist that we should instead replace his name by an 
adjective or a circumlocution? What would we say if someone outside our field 
asked us not to talk about a Bragg reflection, or the Ewald sphere, or the Laue 
method, but to use instead some clever adjective or a noun-phrase as long as 
the name of a Welsh village to explain what these mean? 

 Again, I think we should have a bit more respect here. When there are 
simple adjectives to describe a mathematical properties, the mathematical 
vocabulary uses it (like a "normal" subgroup). However, when someone has seen 
that a definition by a conjunction of properties (i.e. something describable by 
a sentence) turns out to characterise objects that have much more interesting 
properties than just those by which they were defined, then they are often 
called by the name of the mathematician who first saw that there is more to 
them than what defines them. Examples: Coxeter groups, or Lie algebras, or the 
Leech lattice, or the Galois group of a field, the Cayley tree of a group ... . 
It is the name of the first witness to a mathematical phenomenon, just as we 
call chemical reactions by the name of the chemist who saw that mixing certain 
chemicals together led not just to a mixture of those chemicals.

 So why don't we give Sohnke what belongs to him, just as we expect other 
scientists to give to Laue, Bragg and Ewald what we think belongs to them? 
Maybe students would not be as refractory to the idea as might first be thought.


 With best wishes,
 
  Gerard.

--
On Fri, May 02, 2014 at 05:42:34PM +0100, Jrh Gmail wrote:
> Dear George
> My student class would not find that IUCr dictionary definition helpful. What 
> they do find helpful is to state that they cannot contain an inversion or a 
> mirror. 
> To honour Sohnke is one thing but is it really necessary as a label? You're 
> from Huddersfield I am from Wakefield ie let's call a spade a spade (not a 
> 'Black and Decker'). 
> Cheers
> John
> 
> Prof John R Helliwell DSc
> 
> > On 2 May 2014, at 17:01, George Sheldrick  
> > wrote:
> > 
> > In my program documentation I usually call these 65 the Sohnke space 
> > groups, as defined by the IUCr: 
> > http://reference.iucr.org/dictionary/Sohnke_groups
> > 
> > George
> > 
> > 
> >> On 05/02/2014 02:35 PM, Jim Pflugrath wrote:
> >> After all this discussion, I think that Bernhard can now lay the claim 
> >> that these 65 space groups should really just be labelled the "Rupp" space 
> >> groups.  At least it is one word. 
> >> 
> >> Jim
> >> 
> >> From: CCP4 bulletin board [CCP4BB@JISCMAIL.AC.UK] on behalf of 
> >> Bernhard Rupp [hofkristall...@gmail.com]
> >> Sent: Friday, May 02, 2014 3:04 AM
> >> To: CCP4BB@JISCMAIL.AC.UK
> >> Subject: Re: [ccp4bb] Confusion about space group nomenclature  .
> >>  
> >> Enough of this thread.
> >>  
> >> Over and out, BR
> > 
> > 
> > --
> > Prof. George M. Sheldrick FRS
> > Dept. Structural Chemistry,
> > University of Goettingen,
> > Tammannstr. 4,
> > D37077 Goettingen, Germany
> > Tel. +49-551-39-33021 or -33068
> > Fax. +49-551-39-22582

Re: [ccp4bb] Confusion about space group nomenclature

[Bernhard Rupp]

> namely "chirality-preserving".

enantiostatic ;-) ?

BR
 

Re: [ccp4bb] Confusion about space group nomenclature

[Ian Tickle]

Bernhard

On 2 May 2014 21:51, Bernhard Rupp  wrote:

>
> Nonetheless, this does not necessarily discredit my quest for a
> descriptive adjective, and the
> absence of such after this lively engagement might indicate that the
> question was not quite as
> illegitimate as it might have appeared even to the cognoscenti at first
> sight. Nonetheless,
>
> a toast to Sohncke!
>

I second that, but while not intending in any way to belittle Sohncke's
contribution to the subject, I would point out that Sohncke is a noun (of
kind "proper noun") and most definitely not an adjective (of any kind).  I
say that because I have been working all along on the assumption that your
quest was for an adjective (i.e. as you say above, a descriptor of a noun).

In the English language at least, adjectives come in 5 different flavours:
1) attributive ("the good book"), 2) predicative ("this book is good"), 3)
absolute ("this book, good though it is, won't win the Booker", 4) nounal
adjective ("the good, the bad and the ugly"), and 5) postpositive
(adjective follows noun: mostly archaic usage in English though common
syntax in other languages).  Of course nouns can also function as
adjectives ("adjectival noun") but only in a very limited way.  In
particular nouns can only function as attributive adjectives ("a Sohncke
space group").  You can't use a noun as a predicative adjective ("this
space group is Sohncke" just doesn't sound right), or use an adjectival
noun in any of the other 3 ways; it can only function as the attribute of
another noun.  A true adjective can be used in all 5 ways without breaking
the syntactical rules, e.g. the attributive "a centrosymmetric space group"
and the predicative "this space group is centrosymmetric" are both valid
syntax (I hesitate to use the "e" word again having had it ruled totally
out of contention).  Exceedingly descriptive though it is,
"chirality-preserving" is technically also not an adjective (it's an
adjectival phrase), though of course that's no reason to rule it out.

Some proper nouns (mostly names of mathematicians for some reason!) have
been transformed into real adjectives (e.g. "Hessian" in honour of Ludwig
Otto Hesse, "Wronskian" for Józef Hoene-Wronski, and several others).
Sadly Sohncke is not one of those in common, or indeed any, usage in
adjectival form (I would hesitate to suggest "Sohnckian" as the adjective
derived from the proper noun).  As an aside, strangely many of these
name-derived adjectives have made the reverse journey and now double as
true nouns themselves, having dropped the nouns to which they were
originally attached.  "Hessian" as a true noun (i.e. not even a nounal
adjective) is of course now used in preference to and is a synonym for the
original "Hessian matrix", "Wronskian" is used instead of "Wronskian
determinant", etc.

Enough of this drivel.  You can tell it's the weekend, and that none of us
have anything better to do ...

Cheers

-- Ian

Re: [ccp4bb] Confusion about space group nomenclature

[Ronald E Stenkamp]

Bernhard is giving me too much credit.  I just told him I'd seen someone's name 
associated with the 65 space groups, but that's the only information I 
provided.  Ron

On Fri, 2 May 2014, Bernhard Rupp wrote:


Fellows,

my apologies for having sparked that space war.
I wish to interject than in my earlier postings to this thread
to Howard I did give credit to the '65 sons of Sohnke' (albeit sans c).

If we honor him, we ought to spell him right.
http://reference.iucr.org/dictionary/Sohnke_groups
Sohnke (IUCr)
Sohncke (same page, IUCr)
Sohncke (Wikipedia and German primary sources):
http://www.deutsche-biographie.de/sfz80497.html

Ron posted the Sohncke link to me off-line right away and I admit that I 
realized the same by googling
'chiral space groups' which immediately leads you to Wikipedia's space group 
and Sohncke
entry. It also shows (in addition to an interesting 74-group page...) my own 
web list, which imho
erroneously used the improper (no pun intended) adjective 'chiral' for the 65 
Sohncke groups. No more.

Nonetheless, this does not necessarily discredit my quest for a descriptive 
adjective, and the
absence of such after this lively engagement might indicate that the question 
was not quite as
illegitimate as it might have appeared even to the cognoscenti at first sight. 
Nonetheless,

a toast to Sohncke!

BR


-Original Message-
From: CCP4 bulletin board [mailto:CCP4BB@JISCMAIL.AC.UK] On Behalf Of Gerard 
Bricogne
Sent: Friday, May 02, 2014 7:17 PM
To: CCP4BB@JISCMAIL.AC.UK
Subject: Re: [ccp4bb] Confusion about space group nomenclature

Dear John,

What is wrong with honouring Sohnke by using his name for something that he 
first saw a point in defining, and in investigating the properties resulting 
from that definition? Why insist that we should instead replace his name by an 
adjective or a circumlocution? What would we say if someone outside our field 
asked us not to talk about a Bragg reflection, or the Ewald sphere, or the Laue 
method, but to use instead some clever adjective or a noun-phrase as long as 
the name of a Welsh village to explain what these mean?

Again, I think we should have a bit more respect here. When there are simple 
adjectives to describe a mathematical properties, the mathematical vocabulary uses it 
(like a "normal" subgroup). However, when someone has seen that a definition by 
a conjunction of properties (i.e. something describable by a sentence) turns out to 
characterise objects that have much more interesting properties than just those by which 
they were defined, then they are often called by the name of the mathematician who first 
saw that there is more to them than what defines them. Examples: Coxeter groups, or Lie 
algebras, or the Leech lattice, or the Galois group of a field, the Cayley tree of a 
group ... . It is the name of the first witness to a mathematical phenomenon, just as we 
call chemical reactions by the name of the chemist who saw that mixing certain chemicals 
together led not just to a mixture of those chemicals.

So why don't we give Sohnke what belongs to him, just as we expect other 
scientists to give to Laue, Bragg and Ewald what we think belongs to them? 
Maybe students would not be as refractory to the idea as might first be thought.


With best wishes,

 Gerard.

--
On Fri, May 02, 2014 at 05:42:34PM +0100, Jrh Gmail wrote:

Dear George
My student class would not find that IUCr dictionary definition helpful. What 
they do find helpful is to state that they cannot contain an inversion or a 
mirror.
To honour Sohnke is one thing but is it really necessary as a label? You're 
from Huddersfield I am from Wakefield ie let's call a spade a spade (not a 
'Black and Decker').
Cheers
John

Prof John R Helliwell DSc


On 2 May 2014, at 17:01, George Sheldrick  wrote:

In my program documentation I usually call these 65 the Sohnke space groups, as 
defined by the IUCr:
http://reference.iucr.org/dictionary/Sohnke_groups

George



On 05/02/2014 02:35 PM, Jim Pflugrath wrote:
After all this discussion, I think that Bernhard can now lay the claim that these 65 
space groups should really just be labelled the "Rupp" space groups.  At least 
it is one word.

Jim

From: CCP4 bulletin board [CCP4BB@JISCMAIL.AC.UK] on behalf of
Bernhard Rupp [hofkristall...@gmail.com]
Sent: Friday, May 02, 2014 3:04 AM
To: CCP4BB@JISCMAIL.AC.UK
Subject: Re: [ccp4bb] Confusion about space group nomenclature  .

Enough of this thread.

Over and out, BR



--
Prof. George M. Sheldrick FRS
Dept. Structural Chemistry,
University of Goettingen,
Tammannstr. 4,
D37077 Goettingen, Germany
Tel. +49-551-39-33021 or -33068
Fax. +49-551-39-22582

Re: [ccp4bb] Confusion about space group nomenclature

[Sweet, Robert]

I'm watching the periphery of this, having just taught something about The 
Sixty-Five Space Groups a few days ago, but my impression is that you guys have 
too much time on your hands.  If you'd like something really interesting (and 
perhaps useful) to spend your time on, let us know.  We'll put you to work.

BS

From: CCP4 bulletin board [CCP4BB@JISCMAIL.AC.UK] on behalf of Ian Tickle 
[ianj...@gmail.com]
Sent: Friday, May 02, 2014 7:42 PM
To: CCP4BB@JISCMAIL.AC.UK
Subject: Re: [ccp4bb] Confusion about space group nomenclature

Bernhard

On 2 May 2014 21:51, Bernhard Rupp 
mailto:hofkristall...@gmail.com>> wrote:

Nonetheless, this does not necessarily discredit my quest for a descriptive 
adjective, and the
absence of such after this lively engagement might indicate that the question 
was not quite as
illegitimate as it might have appeared even to the cognoscenti at first sight. 
Nonetheless,

a toast to Sohncke!

I second that, but while not intending in any way to belittle Sohncke's 
contribution to the subject, I would point out that Sohncke is a noun (of kind 
"proper noun") and most definitely not an adjective (of any kind).  I say that 
because I have been working all along on the assumption that your quest was for 
an adjective (i.e. as you say above, a descriptor of a noun).

In the English language at least, adjectives come in 5 different flavours: 1) 
attributive ("the good book"), 2) predicative ("this book is good"), 3) 
absolute ("this book, good though it is, won't win the Booker", 4) nounal 
adjective ("the good, the bad and the ugly"), and 5) postpositive (adjective 
follows noun: mostly archaic usage in English though common syntax in other 
languages).  Of course nouns can also function as adjectives ("adjectival 
noun") but only in a very limited way.  In particular nouns can only function 
as attributive adjectives ("a Sohncke space group").  You can't use a noun as a 
predicative adjective ("this space group is Sohncke" just doesn't sound right), 
or use an adjectival noun in any of the other 3 ways; it can only function as 
the attribute of another noun.  A true adjective can be used in all 5 ways 
without breaking the syntactical rules, e.g. the attributive "a centrosymmetric 
space group" and the predicative "this space group is centrosymmetric" are both 
valid syntax (I hesitate to use the "e" word again having had it ruled totally 
out of contention).  Exceedingly descriptive though it is, 
"chirality-preserving" is technically also not an adjective (it's an adjectival 
phrase), though of course that's no reason to rule it out.

Some proper nouns (mostly names of mathematicians for some reason!) have been 
transformed into real adjectives (e.g. "Hessian" in honour of Ludwig Otto 
Hesse, "Wronskian" for Józef Hoene-Wronski, and several others).  Sadly Sohncke 
is not one of those in common, or indeed any, usage in adjectival form (I would 
hesitate to suggest "Sohnckian" as the adjective derived from the proper noun). 
 As an aside, strangely many of these name-derived adjectives have made the 
reverse journey and now double as true nouns themselves, having dropped the 
nouns to which they were originally attached.  "Hessian" as a true noun (i.e. 
not even a nounal adjective) is of course now used in preference to and is a 
synonym for the original "Hessian matrix", "Wronskian" is used instead of 
"Wronskian determinant", etc.

Enough of this drivel.  You can tell it's the weekend, and that none of us have 
anything better to do ...

Cheers

-- Ian