Some time ago, I had a dataset which turned out to be P31 with a dimer sitting on the three-fold axis. The only way I found to process it was to run twinned refinement in CNS with (-h,-k,l) and twinning fraction of 0.5. R/Rfree are 20/24% at 2.4A resolution, so the model must be right at least to some extent. Good news is that I can figure out the dimer, the bad news is that ligand binding site is not quite interpretable (it was missing a loop in MR model and I can't build it from the density I get). So my question is: what is the right way (if any) to improve maps in such a case?
Of course, it's quite possible that the aforementioned loop is simply disordered in which case nothing can be done, I presume. Thanks for your help. -- Edwin Pozharski, PhD, Assistant Professor University of Maryland, Baltimore ---------------------------------------------- When the Way is forgotten duty and justice appear; Then knowledge and wisdom are born along with hypocrisy. When harmonious relationships dissolve then respect and devotion arise; When a nation falls to chaos then loyalty and patriotism are born. ------------------------------ / Lao Tse /
