[phenixbb] When to freeze crystal?

miket at chem.ucla.edu miket at chem.ucla.edu
Wed Oct 13 10:02:44 PDT 2010


Just last week I had crystals on Friday, then by Monday they dissolved back into the drop. I don't really understand how or why this happens, but it does. After experiencing this and complaining about it, I heard several other similar stories from around the department. Lesson learned: if you think you have a decent crystal, freeze it. Having said this, I've also heard of good data being collected from a crystal that was over a year old. Like Bert said, I think that occasionally a crystal survives or even improves over time, but those cases are much more rare than cases where the crystal deteriorates. Do how many crystals do you have? You might try freezing some and saving the others in the drop, then you can see for yourself.

Good luck,

Mike



----- Original Message -----
From: "Nathaniel Echols" <nechols at lbl.gov>
To: "PHENIX user mailing list" <phenixbb at phenix-online.org>
Sent: Wednesday, October 13, 2010 8:44:42 AM GMT -08:00 US/Canada Pacific
Subject: Re: [phenixbb] When to freeze crystal?

On Wed, Oct 13, 2010 at 4:16 PM, J J <phenix.upitt at gmail.com> wrote:
> Hi everyone,
> Sorry to ask a question that is not really related to phenix. I hope someone
> here will be able to help me out.
> I have a few crystals at hand right now, but I will not be able to look at
> them for at least another month or so due to beamline schedule. Do you think
> I should freeze them now or wait till I have my beamtime, or it is crystal
> dependent? Thanks in advance.

(Bert meant to send this to the list, but since he's using the wrong
email address, it went to the list admin instead:)

From: "Van Den Berg, Bert" <Lambertus.VandenBerg at umassmed.edu>
To: "PHENIX user mailing list" <phenixbb at phenix-online.org>
Date: Wed, 13 Oct 2010 11:27:32 -0400
Subject: Re: [phenixbb] When to freeze crystal?
It is crystal dependent, but if they are big enough I would freeze
them now. I  have seen many crystal forms deteriorate over time and
wouldn’t take the risk of that happening. It can happen though that
old crystals get better (presumably due to slow dehydration of the
drop), but I think these cases are fairly rare.

Bert
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-- 
Michael C. Thompson

Graduate Student

Biochemistry & Molecular Biology Division

Department of Chemistry & Biochemistry

University of California, Los Angeles

miket at chem.ucla.edu



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