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: [EMAIL PROTECTED]
****************************************************************
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 <[EMAIL PROTECTED]> 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 <[EMAIL PROTECTED]> 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
