Hi Daniel, Whether or not I would introduce detergents would depend on the behavior of the protein during purification and crystallization. Does it behave well during purification in the absence of detergents? In your crystallization screens, do most of the drops have heavy precipitation? If the answer to the first question is "yes" and the answer to the second question "no" I don't think you would need to complicate screening and add detergents. Of course it is possible that association with the membrane induces a conformation that is more emenable to crystallization, but again I wouldn't expect the protein to behave well in the absence of detergents.
Good luck, Bert On 8/1/10 2:13 PM, "Daniel Bonsor" <[email protected]> wrote: I have a 30kDa protein which I have been trying to crystallize. I have tried in the conventional way using Hampton screens but no luck so far. CD of the protein shows it is folded. However reading the literature I found out it is strongly associated with the inner membrane of H. pylori. This was done by Western blots of the supernatant and membranes. Triton X-100 and N-lauroyl sarcosine were found to release the protein into the supernatant. My question is do I change tactics and try and crystallize it as a membrane protein or try adding a small amount of detergents to the protein and treat it as a soluble protein? Or something else? Thanks in advance for all of your suggestions. Daniel Bonsor
