modelling metal-sulfur clusters
cc691077 at bcm.tmc.edu
Thu Apr 8 15:06:11 EST 1999
We are trying to refine a ferredoxin in which the [2Fe-2S] cluster has
been replaced by [2Ga-2S]. We are modelling gallium using scattering
factors for Ga3+, but for sulfur are using scattering factors from
elemental sulfurs (this is in both X-PLOR and SHELX). Not surprisingly,
we have a lot of positive difference density around the clusters, but it
is particularly centered around the galliums.
Has anyone had experience modelling these clusters? Did you use
scattering factors for S-, or did you let the difference be made up for
in the B-factor or occupancy? Does it matter?
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