Hi Todd, I used to work on PNMT which also is supposedly monomeric and formed a disulfide between monomers in the crystals. See http://www.sciencedirect.com/science/article/pii/S1570963905000968?via=ihub We showed that it was irrelevant to activity.
Cheers Christine Sent from my iPad > On 20 Dec 2014, at 9:52 am, Todd Jason Green <[email protected]> wrote: > > Hello All- > > I have recently determined a domain structure of a larger protein. The > structure shows a clear disulfide bond between two monomers in the asymmetric > unit. I'm trying to figure out if this is an artifact of the crystal packing > or has biological relevance. The protein has been reported to function as a > monomer. If I look at the pool of protein on a SDS-PAGE gel under > non-reducing conditions, I see that a smaller percentage (~15-20%) of the > protein runs as a dimer. In the structure, the association has 2-fold > symmetry with about 29% of the monomeric surface area buried between the > dimer. Can anyone point me in the direction of a paper describing a > non-specific disulfide in a crystal, or perhaps a criteria for assessing > specificity? I will do some functional studies, but I'm looking for some info > on a lazy saturday. > > Thanks in advance. Best- > Todd
