Re: [ccp4bb] symmetry possibilities

2022-07-26 Thread Jorge Iulek
AIL.AC.UK <mailto:CCP4BB@JISCMAIL.AC.UK> Subject: Re: [ccp4bb] symmetry possibilities Dear Jorge, what you write makes sense to me, and I cannot answer your questions. This is just to say that the situation you encounter is not completely uncommon, although most crystallographers wo

Re: [ccp4bb] symmetry possibilities

2022-07-26 Thread Jorge Iulek
Dear Ben, Hi Jorge,    I have had some similar cases. The twin fraction can vary during data collection on the synchrotron (different areas of the crystal can have different twin fractions).     Yes, Ben, this seems perfectly feasible to me. But your observation prompted me to think about

Re: [ccp4bb] symmetry possibilities

2022-07-26 Thread Jorge Iulek
Dear Dom.     Yes, Zanuda must also give more insights, well pointed (it goes straight to my question "Should I look at anything else to establish twin P1 is the best way to refine this structure?"). By the way, though we have not gone through P1 in/extensively for while, a brief overview

Re: [ccp4bb] symmetry possibilities

2022-07-26 Thread Jorge Iulek
Thank you, Edward, for sharing this. I will read through the (extensive) details of the work. J. On 7/22/22 10:25 PM, Edward A. Berry wrote: As for your second question, whether refining in a lower symmetry affects the R-factors, On 7/20/22 10:10 AM, Jorge Iulek wrote: Related, and a

Re: [ccp4bb] symmetry possibilities

2022-07-23 Thread Ben Bax
Hi Jorge, I have had some similar cases. The twin fraction can vary during data collection on the synchrotron (different areas of the crystal can have different twin fractions). Sometimes this is not a problem and twin refinement works fine - sometimes it is a problem and it is hard to get a

Re: [ccp4bb] symmetry possibilities

2022-07-23 Thread Eleanor Dodson
board On Behalf Of Kay > Diederichs > Sent: 20 July 2022 22:11 > To: CCP4BB@JISCMAIL.AC.UK > Subject: Re: [ccp4bb] symmetry possibilities > > Dear Jorge, > > what you write makes sense to me, and I cannot answer your questions. This > is just to say that the situ

Re: [ccp4bb] symmetry possibilities

2022-07-23 Thread Dom Bellini
Hi Jorge, > > Should I look at anything else to establish twin P1 is the best way to refine > this structure? You could feed your refined model and map coefficients to Zanuda (CCP4 program) which automatically will check which higher symmetry space group will give lower Rfactors in

Re: [ccp4bb] symmetry possibilities

2022-07-22 Thread Edward A. Berry
As for your second question, whether refining in a lower symmetry affects the R-factors, On 7/20/22 10:10 AM, Jorge Iulek wrote:     Related, and a question I mentioned before in this forum: what if a genuine 2 axis (say , P222 to P2, or even to P1) (I do not mean this is the case here) is

Re: [ccp4bb] symmetry possibilities

2022-07-22 Thread Jorge Iulek
Thanks Kay and Ralf for your input. I will check out the reference pointed and search for more. Best wishes, Jorge Forwarded Message Subject:symmetry possibilities Date: Wed, 20 Jul 2022 11:10:04 -0300 From: Jorge Iulek To: CCP4BB@JISCMAIL.AC.UK Dear

Re: [ccp4bb] symmetry possibilities

2022-07-21 Thread Flaig, Ralf (DLSLtd,RAL,LSCI)
This paper by Pietro Roversi might help: https://journals.iucr.org/d/issues/2012/04/00/ba5182/index.html Kind regards, Ralf -Original Message- From: CCP4 bulletin board On Behalf Of Kay Diederichs Sent: 20 July 2022 22:11 To: CCP4BB@JISCMAIL.AC.UK Subject: Re: [ccp4bb] symmetry

Re: [ccp4bb] symmetry possibilities

2022-07-20 Thread Kay Diederichs
Dear Jorge, what you write makes sense to me, and I cannot answer your questions. This is just to say that the situation you encounter is not completely uncommon, although most crystallographers would abandon such a crystal form, I guess. The technical term that describes this 4-fold twinning

[ccp4bb] symmetry possibilities

2022-07-20 Thread Jorge Iulek
Dear all, We had some data collections at a Synchrotron. Crystals are a kind of brush like (lattice strains, to use a term by Dr. Bergfors, though we employed good effort for purification), but we took advantage of the Synchrotron microfocus.     Some of the datasets (images) clearly