Dear SHJ, there is no reason to expect that the 3D structure of two molecules within the same asymmetric unit are identical even if their chemical formula is identical.
These two molecules experience slightly different crystal packing contacts are are expected to be different. Obviously, in general they are very similar (like in your case), unless the crystallization DG is enormous - which means larger that the folding DG. Oliviero On Tue, March 24, 2009 15:49, Sang Hoon Joo wrote: > I am refining my crystal structure in which I have two identical > chains in one asymmetric unit. > Space group is H32 and each chain yields me a biological trimer as > expected. > The problem is, do I have to assume they are identical, or they are > really different. > After each cycle of refinement, if I try to align two molecules I get > ~ 0.17 RMSD. > -- > Sang Hoon Joo, PhD > Postdoctoral Associate > Duke University > 239 Nanaline H. Duke > Box 3711, DUMC > Durham, NC 27710 > >
