Wolfram,
Did you solve these structures independently by molecular replacement ?
It sounds like your two solutions might be related by alternative
origins (0,1/2 along a,c). If you translate the second example along
the a axis by -a/2 does it refine with similar R-factors ?
Phil Jeffrey
Princeton
On 4/19/12 1:35 PM, wtempel wrote:
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
