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I know this doesn't address your actual question, but since you say the rods are hollow for "most" of their length, is there a not-hollow part that might be large enough to shoot with a narrow synchrotron beam? Your crystals sound similar to some that I worked with, although in my case the hollow imperfections did not extend so deeply, and I found that I could shoot through the middle of the rod avoiding the hollow area, and get very nice diffraction. Evette S. Radisky, Ph.D. Assistant Professor and Associate Consultant II Mayo Clinic Cancer Center Griffin Cancer Research Building, Rm 310 4500 San Pablo Road Jacksonville, FL 32224 (904) 953-6372 (office) (904) 953-2857 (lab) -----Original Message----- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Patrick Loll Sent: Tuesday, December 05, 2006 1:32 PM To: [email protected] Subject: [ccp4bb]: reducing crystal imperfections *** For details on how to be removed from this list visit the *** *** CCP4 home page http://www.ccp4.ac.uk *** We have a system where we can produce rod-shaped crystals that show a classic depletion imperfection--the rods are essentially hollow for most of their length, suggesting that growth is proceeding in this direction more rapidly than fresh protein can diffuse into the area (picture a long hexagonal rod with a perfect conical hole bored into one end, extending for most of the rod's length). Simple-minded optimization experiments (e.g., [PEG] vs. [salt] vs. pH) have clear-cut effects on nucleation, but don't seem to alter crystal shape, which I interpret as meaning that growth occurs rapidly once nucleation has taken place. What are peoples' thoughts on improving the morphology? We're currently exploring whether additives can selectively poison growth along the long axis, but I'd be curious to hear other ideas. For example, might gels help, or are they mainly effective in controlling nucleation? They ARE pretty cool looking. I wonder if there's a market for nanovases... Pat ------------------------------------------------------------------------ --------------- Patrick J. Loll, Ph. D. (215) 762-7706 Associate Professor FAX: (215) 762-4452 Department of Biochemistry & Molecular Biology Director, Biochemistry Graduate Program Drexel University College of Medicine Room 10-102 New College Building 245 N. 15th St., Mailstop 497 Philadelphia, PA 19102-1192 USA [EMAIL PROTECTED]
