Dear All: I use Refmac5 to refine my structure model.
When I set the sigma value to 0.3 (as recommended from tutorial), the resulted model has many red-bars by coot validation (geometry, rotamer, especially, Temp Facotr). I then lower the sigma value to 0.1, the resulted model is much improved by coot validation. I then lower the sigma value to 0.01, the resulted model is almost perfect, by coot validation and Molprobity. My question is: what is the risk for very low value sigma value? Thank you for your advice Ros
