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Fengxia, To me the diffraction appears as if the crystals did not freeze well. So the best option seems to be annealing (as already suggested) or to try different cryo-protectants. Did you perform a room-temperature mount? If so, were the spots nice and round (suggesting the cryo is the cause of the smears)? I would suggest growing your crystals in the presence of cryo as well. Glycerol, PEG 400, all the usual suspects. May I suggest 2-methyl-2,4-pentanediol (MPD). I have had success adding to well (10 - 20 %) but not in crystal drop, then using 20% as a cryo (MPD acting to slow diffusion to give better ordered crystals). Kelly Daughtry ******************************************************* Kelly Daughtry PhD Candidate Department of Physiology and Biophysics Boston University School of Medicine 590 Commonwealth Ave R 390 Boston MA, 02215 (P) 617-358-5548 ******************************************************* On Thu, Jan 21, 2010 at 9:07 AM, Brad Bennett <[log in to unmask]> wrote: > Hi Fengxia- > How about increasing the PEG% so you don't have to add as much "other" > cryoprotectant? > > Also, have you tried annealing the crystals? I've had success with this when > I've had samples diffract similarly. The simplest way is by blocking the > cryostream for 2-3 seconds (repeat 1-2 times) and then shoot. More involved > way is by actually dismounting your crystals back into cryo buffer for 20-30 > seconds, then remounting and shooting. > > HTH- > Brad > > On Thu, Jan 21, 2010 at 1:54 AM, Fengxia Liu <[log in to unmask]> wrote: >> >> Dear all, >> >> I am trying to diffract one semet-protein, it gave me some clear spots and >> some smeared spots in one diffration, you can find maps attached. >> Mother liquor condition is 0.1MTris-HCL pH8.5+10% PEG4k + 0.2M Li2SO4, I >> have tried mother liquor+25%glycerol, paratone, paratone+ mineral oil, but >> they all gave me such pattern. >> Does anyone know how to solve this? I appreciate any advice. >> >> Thank you in advance. >> >> Best wishes, >> Fengxia >> >> >