Hi Deliang, I have an experience with soft crystals:
I used to work with a protein which crystallized fine and diffracted fine. However, after opening the crystallization well few times, crystals turned soft and they stopped diffracting. If I remember correctly, letting crystals sit for a long time (without opening the wells) also caused "softening" of crystals. I suspected polymerization but did not experiment with it. Adding huge amounts of reducing agent helped preserve the "hardness" of crystals little longer. Transferring the crystallizations experiments into the cold room also helped. Bottom line is that soft crystals didn't diffract. Good luck, Nukri Ruslan Sanishvili (Nukri), Ph.D. GM/CA-CAT, Bld. 436, D007 Biosciences Division, ANL 9700 S. Cass Ave. Argonne, IL 60439 Tel: (630)252-0665 Fax: (630)252-0667 [EMAIL PROTECTED] <mailto:[EMAIL PROTECTED]> ________________________________ From: CCP4 bulletin board [mailto:[EMAIL PROTECTED] On Behalf Of deliang Sent: Friday, November 14, 2008 3:28 PM To: CCP4BB@JISCMAIL.AC.UK Subject: [ccp4bb] off-topic: soft crystals? Hi there, Do you ever have experience with the diffraction quality of soft crystals? I just harvested some. They are 30K membrane protein, growing 10 months, size ~0.6mm*0.2mm*0.02mm, but as soft as a hair, no sharp surfaces. We don't have synchrotron time in a few months and no experience with such crystals. Right now we need to decide whether we should use similar conditions for further screening or should change completely methods(from sitting drop to lipid cubic phase), and detergents. Any comments about your work with soft crystals are really helpful. Many thanks. Deliang
