Hello all,
I am puzzled by this situation:
I have two different crystal of the same protein, in the presence, one in
the absence of a ligand.
Both structures refine nicely in space group P21.
Cell constants (a,b,c,beta) are (i) 61,124,61,119 (a<c by a hair) and (ii)
59,125,61,118. There is a SINGLE protein molecule in the ASU. To
facilitate future analysis and comparison between both structures, I have
tried (incl. reindexing) to refine both structures with as similar as
possible translational/rotational states as possible. A failed to do any
better than having them offset by approx. 32A exactly along the a-xis.
Considering the pseudo-hexagonal cell and the extent of the offset being so
close to a/2, c/2 or b/3, I have the feeling that I am missing something.
What could it be?
Thank you as always.
Wolfram Tempel
