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On Saturday 23 December 2006 09:09, Page, Rebecca wrote:
>
> I am refining a structure with a selenomethionine residue in refmac.
>
> The b-factor for the SeMet CE atom is a factor of 10 less than that of
> the Se (Se ~40, Ce ~4).
Usually there are multiple conformations of the side chain,
in which the CE and S[e]D occupy various spots within a
larger locus of electron density. If you model only one of
these, then the CE under-represents the local density while
the Se/S over-represents it.
Ethan
--
Ethan A Merritt
Biomolecular Structure Center
University of Washington, Seattle 98195-7742
