Firstly - please forgive my last 'blank' message - comes of trying to e-mail whilst travelling on a train!
I would suggest that you change the affinity tag that you're purifying with. Go with either a GST or Strep-tag. That way you are avoiding the imidazole that is obviously causing problems with your particular protein. Of course you should also try all the other excellent suggestions; for what it's worth my favourite buffer is Hepes... I would also try other kinds of IMAC resin, such as Talon, where the coordination of the bound metal is much tighter - and where the metal is not Nickel. I've had problems previously with metal leaching into my protein, causing precipitation and aggregation. Good luck. Antony. -- Dr Antony W Oliver Cancer Research UK: DNA Repair Enzymes Group Section of Structural Biology The Institute of Cancer Research 237 Fulham Road LONDON SW3 6JB [EMAIL PROTECTED] 020 7153 5488 -- The Institute of Cancer Research: Royal Cancer Hospital, a charitable Company Limited by Guarantee, Registered in England under Company No. 534147 with its Registered Office at 123 Old Brompton Road, London SW7 3RP. This e-mail message is confidential and for use by the addressee only. If the message is received by anyone other than the addressee, please return the message to the sender by replying to it and then delete the message from your computer and network.
