Dear Crystallographers,
Thank you very much Andrew, David, and Jacob (as well as others outside of the
BB) for very helpful input on this problem. It does in fact appear that I have
a very nice, statistically disordered structure.
In published structures containing statistical disorder authors have placed the
different proteins in density according to knowledge from previous structures,
and assigned occupancy of 0.5 to the entire chain. This is not possible in my
case: I have a large, heteromeric ring, and one of the reasons for solving the
structure in the first place was to characterise the arrangement of the two
different proteins in the ring. Instead, I would like to build a consensus
model, which represents both proteins. The resolved regions of each protein are
extremely similar in primary sequence, and so, in the positions where the amino
acids differ, I intend to prune the side chain either to the last common atom
or to Ala, and name the residue a generic name (DLR, for DuaL Residue for
example). I'd be interested to know if this a reasonable approach, and whether
others have done a similar thing before?
The N-termini of the two proteins (not resolved) differ meaning that while the
resolved regions are very similar in sequence the chain numbering differs. Is
there a sensible way to account for this in a consensus chain? Is it reasonable
to adopt chain numbering of one of the two proteins?
Thank you very much,
Graham
