There are plenty of reports (some even successful) where small concentrations of proteases have been used to enable crystallisation (with soluble proteins). Having put the effort into getting your material in the first place it's a small extra step to try. The professional way is to run a time coarse proteolysis and analyse the protein fragment you get or you can just add a bit of you favourite protease to the drop. I guess if your complex is stable enough it might survive this treatment.
There are companies that will raise specific antibodies, scFvs or other immunoglobulin (and possibly non-immunoglobulin) like molecules to your components or complex using technologies like phage/ribosome display. From experience this option could be very time consuming and expensive requiring much iteration. Generating entities with sufficient affinity that bind a desirable epitope and producing them on a crystallisation scale is not easy. You could screen more conditions but there is a law of diminishing returns (redundancy in crystallisation conditions) Try the simple things first... 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 Theresa Hsu Sent: 28 June 2012 13:26 To: CCP4BB@JISCMAIL.AC.UK Subject: [ccp4bb] Crystallization with antibody Dear crystallographers Trying to crystallize a membrane protein complex of 100 kDa with a soluble protein of 20 kDa which is interact with the membrane protein. So far, no co-crystals in > 200 conditions. Some conditions gave crystals but mass spec of crystals show only either one protein present. I am thinking of antibody but don't know where to start. Can I use the anti-His tag antibody? Thank you.
