Re: [ccp4bb] Off topic: ask about cryoprotectant selection using lithium sulfate as precipitant for crystal growth

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From: Paul Emsley paul {- dot -} emsley {- at -} BIOCH {- dot -} OX {- dot -} AC {- dot -} UK
Date: 2008-02-27

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Subject: Re: Off topic: ask about cryoprotectant selection using lithium sulfate as precipitant for crystal growth
From: Jim Pflugrath jim {- dot -} pflugrath {- at -} RIGAKU {- dot -} COM
Date: 2008-02-27

Subject: Re: Off topic: ask about cryoprotectant selection using lithium sulfate as precipitant for crystal growth
From: "R {- dot -} M {- dot -} Garavito" garavito {- at -} MSU {- dot -} EDU
Date: 2008-02-27

Donghui,

We have several membrane proteins crystallized in salt-based
conditions, actually in high sodium citrate. Yes, LiCl or lithium
formate are good alternatives, but also try lithium citrate, as
citrate also depresses the freezing point quite well.

Good luck,

Michael

****************************************************************
R. Michael Garavito, Ph.D.
Professor of Biochemistry & Molecular Biology
513 Biochemistry Bldg.
Michigan State University
East Lansing, MI 48824-1319
Office: (517) 355-9724 Lab: (517) 353-9125
FAX: (517) 353-9334 Email: garavito@msu.edu
****************************************************************

On Feb 27, 2008, at 12:36 AM, wu donghui wrote:

> Dear Lokesh,
>
> Actually I have tried to dip my crytal directly into mineral oil,
> no ice ring, but also no diffraction, which might indicate crystal
> packing under mineral oil is not stable. Anyway, thanks a lot for
> your valuable information. Other friends mention the use of LiCl or
> Lithium formate as cryoprotectant, I will try these immediately and
> will let you know if it works.
>
> Best regards,
>
> Donghui
>
>
> On 2/27/08, Lokesh Gakhar wrote:
> Hi Donghui,
>
> Have you tried mineral oil? That has sometimes worked for us when
> other cryoprotectants have given problems.
>
> -Lokesh
>
>
> On Tue, Feb 26, 2008 at 9:30 PM, wu donghui wrote:
> Dear all,
>
> Recently, I got a crystallization condition as 0.1 M Bis tris ph
> 6.5, 1.3M lithium sulfate, 0.1M NaCl, the shape of crystals is
> needle cluster, very difficult to grow bigger, microseeding does
> not work, then I tried macroseeding, and found crystal can grow
> bigger and rod like. However as for the cryoprotectant, crystal
> will dissolve in glycerol, ethylene glycol, MPD and PEG, even in
> the very low concentration about 5%. I found my crystal can grow
> under the additive 2-propanol in addition to the above mentioned
> crystallization condition. I also noticed that Hampton
> cryoprotectant kit has the 2-propanol as cryoprotectant. I want to
> know if anyone have ever used 2-propanol as the cryoprotectant and
> what effect it might be. By the way Hampton also mention lithium
> sulfate can be used as cryoprotectant, the recommended maxium
> concentration is 2M, I tried and found ice ring is severe and it is
> very easily to form lithium sulfate salt crystal at this high
> concentration, I also tried sodium malonate, the diffraction gave
> me few spots, resolution is only about 6--7 angstrom.
>
> Does anyone encounter such problem by lithium sulfate?
>
>
> Welcome to any replies. Thanks a lot in advance.
>
> Donghui
>
>

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CCP4bb <-- 2008 <-- February 2008 <-- 27 February 2008

Previous message:
Subject: Re: torsion restraints COOT
From: Paul Emsley paul {- dot -} emsley {- at -} BIOCH {- dot -} OX {- dot -} AC {- dot -} UK
Date: 2008-02-27