I've seen this effect too. In the case I saw the drops were growing (and spreading) due to a reverse diffusion gradient. Optimised conditions used "salting in" method i.e. crystallising as the [pptnt] decreases during equilibration due to dilution as water is Tx from well to drop. Rare but not unknown.
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 Eva Bligt-Lindén Sent: 07 November 2012 12:07 To: CCP4BB@JISCMAIL.AC.UK Subject: [ccp4bb] Problems in crystallization Dear ccp4 users, I have a problem in the crystallization of my target protein. Whenever I set up a vapour diffusion experiment, either hanging or sitting drops, the drops spread out. The surface tension is completely lost in 80-90% of the droplets. Have any one experienced something similar? What could be the reason for this strange behaviour? I have tried three different commercial screens with 96 condition each and there is no difference between the screens. There is no difference between manual or robotic setups either. The protein buffer is 40 mM Tris, 2 mM MgCl2 buffer, pH 7.4. The buffer controls are all ok. Kind regards, Eva ____________________________________ Eva Bligt-Lindén (M.Sc.) PhD student Structural Bioinformatics Laboratory Department of Biosciences, Åbo Akademi University BioCity, Tykistökatu 6A FI-20520 Turku Finland
