If you have good and bad crystals in the same drop, I've had success pushing a crummy crystal into a good crystal and having it release that way.
Additionally, once I realized this was going to be a long term problem, I started coating the sitting drop depressions with a thin layer of vacuum grease. The crystals just slid right off the grease and I never saw any changes in the diffraction data to suggest the grease was giving me issues. Chris On Wed, 28 Jan 2009, Savvas Savvides wrote: >>>Dear colleagues, >>> >>>we have been growing crystals of a protein complex in sitting-drop geometry >>>that stick to the bottom of the drop remarkably well. It's as if they are >>>glued onto the plastic. This makes crystal handling next to impossible >>>without destroying the crystals. We have tried whiskers, loops, all kinds of >>>micro-tools, and pipetting techniques to no avail. I can say at the outset >>>that we have been unsuccessful in growing these crystals in hanging-drops or >>>at 4 degrees. Deglycosylating the complex also leads to nowhere. In fact, we >>>are only able to get crystals from homogeneously glycosylated protein >>>produced in HEK293S/I- cells. >>> >>> >>> >>> In the meantime we are playing with the idea of siliconizing the >>>sitting-drop depressions to alter the crystal/plate interface. But then >>>again, nucleation events on the plastic may be the reason we are getting >>>crystals in the first place. We have also thought of trying microseeding to >>>have more control on nucleation issues. Our protein production is quite >>>limiting and forces us to be very selective with our experimentation. >>> >>> >>> >>>Nonetheless, while we are waiting for fresh material to explore some of >>>these ideas we would like to make the most out of the crystals we have grown >>>thus far. We would therefore very much appreciate any input/ideas on >>>manipulating these crystals for data collection. >>> >>> >>> >>>Best wishes >>> >>>Savvas >>> >>> >>> >>> >>> >>>---- >>>Savvas Savvides >>>L-ProBE, Unit for Structural Biology >>>Ghent University >>>K.L. Ledeganckstraat 35 >>>9000 Ghent, BELGIUM >>>office: +32-(0)9-264.51.24 ; mobile: +32-(0)472-92.85.19 >>>Email: savvas.savvi...@ugent.be >>>http://www.lprobe.ugent.be/xray.html >>> >>> >>> >>> >>> >>> >>> >>>From: CCP4 bulletin board [mailto:ccp...@jiscmail.ac.uk] On Behalf Of >>>Katarina Moravcevic >>>Sent: Tuesday, January 27, 2009 10:52 PM >>>To: CCP4BB@JISCMAIL.AC.UK >>>Subject: [ccp4bb] pseudo translation >>> >>> >>> >>>Hi all, >>> >>>here is a question from a beginner. I have a home source data set that >>>indexed and scaled in a P2 space group (a=46.704,b=59.362, c=48.783, >>>alpha=90.0, beta=104.469, gamma=90.0) with predicted 2mol/au. After failing >>>to get a MR solution with Phaser I ran the phenix.xtriage which showed that >>>I have a large (89.18) Patterson peak at 0.5 0 0.5 which indicates pseudo >>>translational symmetry. I was wondering if there is anything I could do with >>>this data to get around this problem. Given that I don't have a lot of >>>experience any suggestion/explanation would be fantastic. >>> >>>Thanks in advance >>> >>>K >>> >>> >>> >>> >>> >>>E-mail message checked by Spyware Doctor (6.0.0.386) >>>Database version: 5.11630 >>>http://www.pctools.com/en/spyware-doctor-antivirus/ >>> Christopher L. Colbert, Ph.D. Instructor Phone: (214) 645 5944 University of Texas Southwestern Medical Center FAX: (214) 645 5945 6001 Forest Park Lane Dallas, TX 75390
