Dear Artem,
Thanks for your very comprehensive reply. At the risk of reaping further
criticism,
I will now do little more than just reiterate my earlier comment: that from the
feedback
that we receive, the PX Scanner is much valued by the number and range of groups
that are now using these systems.. and even for some very small crystals !!
Also, I am pleased to confirm our invitation for you to collect data with us,
wherever
and whenever might be mutually convenient. Alternatively, you may be quite
content
that only your own Grandma's apple pie ever need be tasted.
Many Thanks and Best Regards,
Marcus Winter (Agilent Technologies)
From: Artem Evdokimov [mailto:[email protected]]
Sent: 19 April 2011 13:30
To: WINTER,MARCUS (A-UnitedKingdom,ex1)
Cc: [email protected]
Subject: Re: [ccp4bb] viewing and scoring diffraction using the PX Scanner
Hi Marcus,
I think you misinterpret my comments :) My first point is not that my specific
proteins make it easy to distinguish salt from protein visually - it's rather
that I am experienced enough and also know enough chemistry to make an educated
conclusion about the contents of my drops. I expect this to be an entirely
trainable skill since only very rudimentary inorganic chemistry knowledge is
sufficient to knock off about 80% of all salt crystals based simply on the
knowledge of drop contents, and the rest is experience that anyone with 1-2
years of crystallization practice can obtain.
The crystal challenge while entertaining is nothing like the real world. In the
real world I know what's in my drop, and in the real world I yet have to
encounter a situation with TWO crystals in one drop of which only ONE is good,
and the other will DIE as soon as I harvest the other one. This is too
dramatic. Is this some sort of a Shroedinger crystal? Are the two crystals
quantum-entangled? Crystallization is not a game, and if I only have one good
crystal *ever* then I am not likely to get a structure, even if I know where
that crystal is (we're talking new structure here, not a soak of a compound or
a close MR, in which case there should not ever be only one crystal). Why don't
I have more drops like this so I can harvest a couple of different crystals and
get an actual dataset in the process? Come on. Likewise, most of the crystals
in the challenge are way too huge - most hits aren't anywhere near that size
which makes me wonder about the usefulness of the device in question for small
nasty crystals - which are by far more common than the fat shiny ones that
feature prominently in the challenge.
On the subject of finding 'the best' crystals in a drop, or in a plate: if this
was an actual syncrotron-quality beam capable of telling me right away that
some of my 10x20x10 micron crystals are better than others then I would be much
more curious. I however doubt that the instrument in question is very useful
for crystals that are smaller than say 100x50x50 micron (assuming modest unit
cell dimensions).
As to the price - like you say the proof is in the pudding. The word
'considerable' is subject to *considerable* variance of meaning. For example,
the actual price can be $390K which is a price of a cheap car's worth less than
my original estimate of $400K -- is this considerable or not and more
importantly is it still too much with respect to the value/price ratio? To me
personally $10K is a lot, but the price/value ratio is still not favorable, the
price would have to be around $80-90K to become interesting to me personally. I
understand that it is not likely that the instrument of this sort can cost this
little with today's technology. Which is why the cost/value matters :)
Suppliers are reluctant to post specific prices of non-commodity items because
then everyone would want to negotiate down from the same position - that's
understandable, but I am not an equipment manufacturer and therefore I can
understand but I do not have to sympathize. Without the actual price you can't
really argue.
And that's what brings me to the point that several others have made, which is
that the etiquette of this board has always been to avoid direct advertisement.
In my opinion it would have been more tactful to comment that 'direct X-ray
study of crystals in-situ is a cool way to discover interesting things about
your crystals' and leave the specific instrument that you sell to be discovered
by whoever wants to dig deeper.
Cheers,
Artem
On Tue, Apr 19, 2011 at 2:22 AM,
<[email protected]<mailto:[email protected]>> wrote:
Dear Artem,
Thanks for your reply. You raise a number of points.
Immediately, I should comment that the price of the PX Scanner is very
considerably less than the $400k that you mention.
Whilst - with the proteins and crystallisation conditions that you may be
working
with, visual inspection may be sufficient to differentiate salt from protein
crystals (as you suggest), you will accept that generally this may not be the
case. Thus, 'direct' inspection, using X-rays, must surely be the most
appropriate way ?
As you will be aware, the best looking crystals are seldom the best diffracting.
This is well demonstrated through the PX Scanner 'Crystal Challenge', of course.
Clearly, that's another prime purpose of the PX Scanner: to identify the 'best'
crystals
from amongst a multitude of candidates in a single droplet or across a plate,
etc.
Also, using the PX Scanner, we can check the effect of added cryo-protect.
prior to
freezing.
Therefore, with this range of uses, the PX Scanner is clearly not intended for
full
'data-collection' - but rather to most effectively support crystallisation
optimisation and
as a complement to in-house and central facility data-collection work. From
the feedback
that we receive, the PX Scanner is much valued by the number of groups which are
now using these systems worldwide.
However, even the proof of Grandma's apple pie is not until the eating.
Accordingly,
we most cordially invite you to visit one of our application labs - or perhaps
one of our
customer sites (by arrangement), with you, hopefully, being able to bring one
or more
of your crystallisation plates for inspection using the PX Scanner system.
Since you
are based in North America, I believe, one of my responsible colleagues will
take up
this invitation with you, off-BB.
We look forward to our continuing discussions - with yourself, and all others
who
may be interested.
Many Thanks and Best Regards,
Marcus Winter (Agilent Technologies)
[https://mail.google.com/mail/html/compose/static_files/blank_quirks.html?ui=2&ik=698a5dc8ca&view=att&th=12f6ca3c13939554&attid=0.1&disp=emb&zw]<http://www.chem.agilent.com/en-US/Products/Instruments/X-raycrystallography/Pages/Crystalchallenge.aspx?cid=4710>
From: Artem Evdokimov
[mailto:[email protected]<mailto:[email protected]>]
Sent: 19 April 2011 02:50
To: WINTER,MARCUS (A-UnitedKingdom,ex1)
Cc: [email protected]<mailto:[email protected]>
Subject: Re: [ccp4bb] viewing and scoring diffraction using the PX Scanner
Hi,
So what's your secret - how did you pack an entire synchrotron into a little
box?
OK, so I am being facetious a little. However, I cannot help asking myself why
would I want to spend so much money on a system that is basically a (vertical)
X-ray diffractometer in a box, with fixed distance, and sans the ability to
collect data? I can only guess that the system costs in the range of $400K (am
I right?) and for that money one could get a pretty nice actual X-ray
diffraction set-up...
Now, if this thing cost say ... $80K I may be interested, although most of our
crystals are so small that this set-up will uniformly score them as 'no idea'
because they don't even diffract at home on a 'real' X-ray source with a CCD.
Artem
P.S. the day I start routinely confusing protein and salt crystals is the day I
stop working in the lab :)
On Mon, Apr 18, 2011 at 3:00 AM, Marcus Winter
<[email protected]<mailto:[email protected]>> wrote:
Dear Chris,
I'm prompted by your posting just to mention the Agilent Technologies
PX Scanner 'Crystal Challenge' at:
www.agilent.com/chem/crystalchallenge<http://www.agilent.com/chem/crystalchallenge>
Thus, the only really useful assessment, or 'score', of objects (putative
crystals) - or crystallisation conditions, is by the actual observed diffraction
characteristics... and these preferably directly in situ, in the horizontal
crystallisation plate, as achieved in the PX Scanner.
Many Thanks and Best Regards,
Marcus Winter (Agilent Technologies)
Error! Filename not
specified.<http://www.chem.agilent.com/en-US/Products/Instruments/X-raycrystallography/Pages/Crystalchallenge.aspx?cid=4710>
From: CCP4 bulletin board
[mailto:[email protected]<mailto:[email protected]>] On Behalf Of Chris
Ulens
Sent: 18 April 2011 08:24
To: [email protected]<mailto:[email protected]>
Subject: [ccp4bb] viewing and scoring crystallization drops on the iPad
Our laboratory has been developing an application to view and score
crystallization drops on the iPad. We would like to know if crystallographers
see potential benefits from the functionality of the iPad to swipe and pinch
through drops. We are looking for specific comments from Formulatrix users, but
other users are also welcome to comment.
http://www.youtube.com/watch?v=LezurNhm0pA
Specific ideas for future development are:
- composition of crystallization buffers on a back-flip of the image drop
- back-sync of crystallization scores on the iPad with the image database
- emailing a drop image to colleague
Thanks.
-Chris
---------------------------------------------------
Chris Ulens, Ph.D.
Lab of Structural Neurobiology
Department of Molecular Cell Biology
Campus Gasthuisberg, ON1
Herestraat 49, PB 601
B-3000 Leuven
Belgium
http://www.xtal.be<http://www.xtal.be/>
