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Thanks for so many quick responses! Actually, I have test several different cryo-protectants, including glycerol, EG, and PEG400. I did not see much differences between these cryo conditions. So, I choose glycerol. I would like to test my crystals in RT. But I don't know how to do this. Just mount crystal to the X-ray machine without cryo stream? Or I should use capillaries? Zhiyi On Wed, Jan 27, 2010 at 5:45 AM, Kelly Daughtry <[log in to unmask]> wrote: > Tascimate can be used as the cryo as well. I have had experience with > crystals in similar condition and moved the crystals to a 20% > increased Tascimate solution and they froze well. > > I agree with Ezra, room temperature mount your crystal before > freezing. It is the only way to know the true problem. > > > Kelly > ******************************************************* > 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 Tue, Jan 26, 2010 at 1:25 PM, Marcus Winter > <[log in to unmask]> wrote: >> Dear Zhiyi, >> >> >> Ezra is exactly right, of course. The Oxford Diffraction PX Scanner >> system can assess the diffraction qualities of (putative) protein >> crystals in situ - in the crystallisation plate. So, directly, you >> would discover if your 'big and beautiful' crystals actually diffract >> well... in their mother liquor under ambient conditions and before the >> addition of any cryo-protect. Do you have a friend or neighbour with >> a PX Scanner ? If not, please feel most welcome to contact >> Oxford Diffraction: we would be pleased to assist if at all possible. >> >> >> Good Luck and Best Wishes, >> >> Marcus Winter. >> >> www.oxford-diffraction.com >> >> >> >> >> -----Original Message----- >> From: CCP4 bulletin board [mailto:[log in to unmask]] On Behalf Of >> Ezra Peisach >> Sent: 26 January 2010 16:01 >> To: [log in to unmask] >> Subject: Re: [ccp4bb] Crystal rescue >> >> First you need to establish if it is your cryo conditions or the >> crystals. Depending where you are - they might have the equipment to do >> >> a wet mount - without freezing. Yes the crystal will not last - but >> then you know if the problem is in the >> crystal. If it is - you need better crystals. If it is the cryo - you >> need to work on that. Tacsimate is mixture of alot of different >> compounds - but the smears are too close together to be a small salt >> crystal on top... >> >> Good luck, >> >> Ezra >> >> On 1/26/2010 10:42 AM, Zhiyi Wei wrote: >>> Dear all, >>> >>> I got a problem with my crystals. I have two total different proteins >>> that both can be crystallized in the condition with PEG3350 and >> Tacsimate >>> (although the concentrations are different) with different shapes. The >>> crystals look big and beautiful. However, when I test them in >> synchrotron, >>> both of these two types of crystals showed poor diffractions. As >> showed in >>> the attached diffraction image, the diffraction is up to ~4 A but >> smear in >>> one direction while<8 A in the other direction. The interesting thing >> is >>> that the diffraction pattern is similar for all crystals (from two >> different >>> proteins) that I tested without exception although they belong to >> different >>> space groups. So, I wonder whether these kind of pattern is caused by >>> Tacsimate (I don't know what it is) and how to rescue these crystals. >> Any >>> suggestions or comments? >>> >>> Thanks a lot! >>> >>> Best, >>> Zhiyi >>> >> >