Hi all,
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been replaced by [2Ga-2S].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?
Thanks,
Chetlen
