On Tue, 2007-03-20 at 08:57 +0100, Laurent Maveyraud wrote: > Dear list, > > another question related to stereochemistry, but concerning coot. > When using the RSR zone button, which should "improve geometry and fit to > map", it seems that the geometry is not always improved : some chiral > centers can be inverted.
That is not always a bad thing. > The surprising thing is that using the "regularize > zone" afterwards does not correct this, even if the chirality of the center > is not set to both, but to positive in the cif dictionary (ie should define > only one possible chirality). > Has anybody else notices this behavior ? Is there a way to adjust the weight > between geometry and map terms in the RSR option ? Chiral volumes are not part of the geometric target function in Coot[1], so changing the weight will have no effect. Currently what I do for chiral volumes (as a work-around) is use Validate -> Incorrect Chiral Volumes to find the building errors. They are trivial to fix when you know where they are. Often I use single atom drag to move the chiral centre to the other side of the chiral plane (made by the chiral neighbours). Paul. [1] They should be, I tried it but it made the minimization slow and unstable. I should try it again.
