Could be a hexacoordinated cobalt with a water molecule (or a hydroxyl ion) depending on the chemical environment...
Artem On Thu, Jul 7, 2011 at 10:07 AM, Machius, Mischa Christian < mach...@med.unc.edu> wrote: > Y'all, > > I was wondering if anyone had any thoughts about a feature we observe with > a metal-binding site: we have a cobalt that is bound by four histidines and > one carboxyl group. There is extra density near the cobalt. See pictures > below. The extra density spans the NE2 atoms from two histidines. The Fo-Fc > peak (green) has a height of up to 10 sigma (eight molecules in the > asymmetric unit, all showing the same feature). > > I placed a water molecule into the density to get some distances: the > distances between the peak and the neighboring histidine NE2 atoms is ~1.8Å > and ~2.0Å, resp. The distance between the peak and the cobalt is ~1.7Å. The > resolution is 1.24Å. > > Any input would be greatly appreciated. > > Many thanks in advance! > > Cheers! > MM > > >
