[ccp4bb] selenomethionine contact

[Alexander U. Singer]

Hi -- I have a case in which I have a refined structure in which the  
'so-far' measured distance between the Se atom of a selenomethionine  
and its crystallographic neighbouring Se atom (same residue) is 2.9 A,  
and I see continuous density between the two atoms.  Has anyone  
subscribing to this newsgroup come across a case in which methionine S  
atoms and/or selenomethionine Se atoms form disulfide/diselenide bonds  
in the crystal, and what does that mean in terms of its possible  
presence biologically?

Thanks for your help
Alex

--
Dr. Alex Singer
C.H. Best Institute
112 College St. Room 70
University of Toronto
Toronto, Canada, M5G 1L6
416-978-4033