RE: [ccp4bb]: beautiful reasonably big crystals from a protein which diffract to 6A at the most.

[Christensen, Jeff]

Hi, Orly,   If you're getting big crystals overnight that don't diffract well, my first thought is to try and slow down the growth of the crystal.  If the faces of the crystal grow at different rates, rapid growth can induce stresses in the crystal that result in poor diffraction.  Try diluting the protein sample 1:1 w/ nanoH20 and then set up vapor diffusion drops with protein:crystallant ratios of 1.5:1, 2.0:1, 2.5:1, etc.  The larger volume of dilute protein will end up at the same final concentration as the drops your setting up now, but through slower protein concentration "in dropo" as the drop moves toward equilibrium.   Also, have you tried mounting the crystals in a capillary rather than freezing, and then checking the resolution?  This will tell you whether it's a problem inherent in the crystal or if your cryo-protectant is creating the problem.   Good luck!   Jeff   Jeff Christensen Senior Research Associate deCODE biostructures 7869 NE Day Rd. W. Bainbridge Island, WA 98110 phone (206) 780-8933 fax (206) 780-8547 [EMAIL PROTECTED] From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Orly Dym Sent: Sunday, November 27, 2005 12:31 AM To: ccp4bb@dl.ac.uk Subject: [ccp4bb]: I have beautiful reasonably big crystals from a protein which diffract to 6A at the most. I have tried adding additives, crystallizing in different methods (hanging, drops, sitting drops and microbatch under oil). The crystals grow over night and contain high percent of water (they are very fragile). I also tried different methods of dehydration (using different PEG's, MPD, glycerol and so on). Currently I am trying to grow them at 4C. Any other ideas as to what I should try in order to improve the resolution? Thanks Orly Dr. Orly Dym Israel Structural Proteomics Center Department of Structural Biology Weizmann Institute of Science http://www.weizmann.ac.il/ISPC 972-8-934-3759 - Tel 972-8-934-4159 - Fax [EMAIL PROTECTED]