Hi Yuri, I've had a very similar experience last week which ended badly. I opted to cryo my new crystals using my favourite cryo. Diffraction showed at least the crystals were protein but not much more. A classic example of cryo killing crystals. I mounted the remaining tiny fragment from the drop in a room temperature mount and got 15 images before it died. From this I got a cell and lattice even though it only diffracted to 6Ang. If had mounted a larger piece of crystal first off I might of been able to get a dataset with much shorter exposures. I would encourage either an in-situ test you have the equipment or use a capillary in whichever way suits. There are methods that allow recovery of the crystal after the test. At least this way you can (a) feel satisfied when you crush it up afterwards for seed because it didn't diffract at all or (b) successfully cryo your nicely diffracting crystal. Good Luck!
David Hargreaves Associate Principal Scientist _____________________________________________________________________ AstraZeneca DECS, CP&SS Mereside, 50F49, Alderley Park, Cheshire, SK10 4TF Tel +44 (0)01625 518521 Fax +44 (0) 1625 232693 David.Hargreaves @astrazeneca.com Please consider the environment before printing this e-mail -------------------------------------------------------------------------- AstraZeneca UK Limited is a company incorporated in England and Wales with registered number: 03674842 and a registered office at 2 Kingdom Street, London, W2 6BD. Confidentiality Notice: This message is private and may contain confidential, proprietary and legally privileged information. If you have received this message in error, please notify us and remove it from your system and note that you must not copy, distribute or take any action in reliance on it. Any unauthorised use or disclosure of the contents of this message is not permitted and may be unlawful. Disclaimer: Email messages may be subject to delays, interception, non-delivery and unauthorised alterations. Therefore, information expressed in this message is not given or endorsed by AstraZeneca UK Limited unless otherwise notified by an authorised representative independent of this message. No contractual relationship is created by this message by any person unless specifically indicated by agreement in writing other than email. Monitoring: AstraZeneca UK Limited may monitor email traffic data and content for the purposes of the prevention and detection of crime, ensuring the security of our computer systems and checking Compliance with our Code of Conduct and Policies. -----Original Message----- From: CCP4 bulletin board [mailto:CCP4BB@JISCMAIL.AC.UK] On Behalf Of Yuri Pompeu Sent: 01 December 2012 01:23 To: CCP4BB@JISCMAIL.AC.UK Subject: [ccp4bb] To cryo or not to cryo... Dear community, I have what seems to be a pretty decent single crystal that grew from a screen set up 2 weeks ago. I am trying to reproduce it but so far I have not succeeded. I am however afraid the crystal that did form will start to deteriorate. So this brings me to dilemma, I feel like I should try and mount this crystal and shoot it. But since I only have 1 sample, I do not want to mess this up... I am inclined to try cryo conditions, but I am afraid the addition of a cryo such as glycerol could destroy the little guy. The crystal formed in 30% PEG 4000, 0.1M NaCitrate pH5.6 and 0.2M NH4AcO, I wonder if this is a cryo condition already? Any suggestions would be appreciated. best,
