*** For details on how to be removed from this list visit the ***
*** CCP4 home page http://www.ccp4.ac.uk ***
Thomas Stout wrote:
> It seems to me that the best solution here would be to model what is
> actually going on: disorder. For the example of a lysine where there
> limited or poor electron density beyond the C-beta, the best
> representation of the physical model would be an ensemble of all
> possible rotamers of what is physically present in the crystal. Havin
> "N" sidechains (alternate conformers) with occupancies of 1/N would be
> extremely clear to all users (novice and expert alike) as well as most
> if not all software.
I agree. I don't know if anyone has attempted it though.
The sidechains could be rigid bodies, reducing the parameterisation
considerably. Group occupancies for each rotamer could then be refined.
B-factors are going to be the problem - this needs thought.
At reasonable resolutions mainchain atoms should probably be split,
which would allow a few degrees of freedom of motion for the sidechain.
It would be interesting to try.
Kevin
