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, CPSS
Mereside, 50F49, Alderley Park, Cheshire, SK10 4TF
Tel +44 (0)01625 518521 Fax +44 (0) 1625 232693
David.Hargreaves @astrazeneca.com
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-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.
