Dear V. are you sure these are crystalline? - I have had similar growth from 'spherulites' that I thought was promising. But then when I went in with a needle to break them for seeding, it turned out they were fibrous not crystalline. This made me think they were a product of denatured protein. So I would say poke them first to check they snap like a crystal would. Actually mine were birefringent in four big sectors similar to the domains in the underlying spherulites (which had a four sectors with opposite quarters the same colour - like the Burundi flag (had to look that up;) ) . My feeling is fibrous protein is not a good crystallization lead..... But maybe you have had better luck Martyn
________________________________ From: venkatareddy dadireddy <[email protected]> To: [email protected] Sent: Wednesday, 21 May 2014, 10:58 Subject: [ccp4bb] Sea Urchin like crystals Dear All, I'm working on 24.3 KDa protein (pI 4.84) with (Asp + Glu): 36 and (Arg + Lys): 16. Protein is in buffer Tris (10mM), pH 7.5. I got sea urchin like crystal clusters @ protein conc 38.5 mg/ml in sitting drop method; condition 0.2M NH4I, 20% PEG3350 & pH 6.8 (PEG/ION A12). These crystals are very thin. I tried different pH values ranging from 6.0 -9.0 with 0.5 units increment, PEG conc. from 10 -30% and NH4I conc. from 0.1 -0.5 M independently in hanging drop method and ended up with NO Crystals. Can somebody suggest strategy to improve crystals. Please find the crystal pic with attachment. Regards, Venkat.
