To add my 2 cents. Recently we have screened a lot of really poor looking crystals. We had tried originally at cryo temps and really were quite unsure as to weather they were protein, just poorly diffracting crystals, etc.. We then mounted some at room temperature and were able to observed reasonably good diffraction. It convinced the researcher who's project it was to start working out decent cryo conditions which they did and we have the initial structure.
I always advocate a room temperature shot just to make sure you have what you think you have. I have seen too many people follow the wrong track because of a couple of inconclusive cryo shots. Finally as an observation over the years the art of mounting a crystal for a room temperature or 4 C shot is a dying art. I am not firmly convince the Mitogen mounts work really well, I have always had better luck with a capillary. That just may be me though. Cheers, Leonard M. Thomas Ph.D. Macromolecular Crystallography Laboratory Manager University of Oklahoma Department of Chemistry and Biochemistry Stephenson Life Sciences Research Center 101 Stephenson Parkway Norman, OK 73019 405-325-1126 [email protected] http://barlywine.chem.ou.edu http://structuralbiology.ou.edu ________________________________________ From: CCP4 bulletin board [[email protected]] on behalf of Jim Pflugrath [[email protected]] Sent: Thursday, February 06, 2014 6:25 AM To: [email protected] Subject: Re: [ccp4bb] Room temperature data collection Clearly, it is always possible to do non-cryogenic data collection simply by not using a cryogenic cooling device and mounting crystals so that they do not dehydrate or dry out. I've been doing quite a lot of room temperature data collection lately because in the home lab we can SAD-phase lysozyme with data collection times of about 30 seconds or so. It would seem that in 30 seconds one would not have a problem with radiation damage from a home source. It would seem. There are many benefits with cryogenic diffraction data collection beyond just the obvious ones. I am in agreement with Enrico Stura. While he may not have exactly said this, I think one should take the time to figure out how to preserve diffraction of their crystals at cryogenic temperatures.
