I hate to take you back to the step of crystallization but have you tried seeding to improve the crystal morphology/volume? If tinkering around with cryoprotectants and mounting techniques does not help your case, seeding might be worth considering. In some of the cases I've seen, my labmate was able to "transform" plates into 3D crystals. Of course, if there's good reason one is getting plates in the first places, seeding may not help. Just to keep that in the back of your mind given the magical "transformations" I've witnessed.
Good luck! Raji On Mon, Apr 1, 2013 at 11:19 AM, Phoebe A. Rice <[email protected]> wrote: > Among many possible reasons, the streaking could be caused mechanical > stress to the thin plates during mounting. Have you tried those loops that > look like miniature tennis rackets? > > Phoebe > > ------------------------------ > *From:* CCP4 bulletin board [[email protected]] on behalf of Rakesh > Chatterjee [[email protected]] > *Sent:* Monday, April 01, 2013 10:01 AM > *To:* [email protected] > *Subject:* [ccp4bb] plate crystal optimization > > hello everyone, > i have a protein which co-purifies with a ligand (small molecule ~ > 810 Dalton). i didn't know what kind of ligand is it so i am planing to > identify it. meanwhile my protein crystallized as plates and while > diffracting i found that the crystal is showing a good diffraction pattern > upto 2.6 Angstroms in home source Cu K-alpha. however when the crystal > rotates between 90 degrees to 135 degrees, the spots become streaky. should > i try different cryo-MPD/ PEG400 etc? to circuvent the problem i did some > additive screen but was not of much help. any valuable suggestion willbe > handfull. > > thanx in advance > rakesh > -- Raji Edayathumangalam Instructor in Neurology, Harvard Medical School Research Associate, Brigham and Women's Hospital Visiting Research Scholar, Brandeis University
