Hello Leonidas-- > > I am trying to refine a crystal structure with RDCs, including NH, NC, > and CaC (and dihedral angles). While NHs and dihedral angles give nice > result, when I include any of the carbon RDCs the algorithm does not > converge due to many violations. I wonder if there is any method to > weight different thos NC and CaC RDCs to influence less than the NH, > if that makes sense. >
1) Please read the paragraph at the top of https://nmr.cit.nih.gov/xplor-nih/doc/current/python/ref/rdcPotTools.html about the RDC sign convention. 2) If you prescale the RDCs (don't use scale_toNH), then you usually will need to weight the energy terms differently, but if you do not prescale the RDCs (and thus use scale_toNH in the script), the energies of the RDCs involving different nuclei should scale appropriately (such that signal to noise is approximately the same) without different weight factors. 3) The number of violations is not such a useful concept for RDCs, as the threshold for violation would generally be different for those of large and small magnitude. Thus, we usually use the R-factor (or possibly chi^2) to assess the goodness of RDC fit. I hope this helps-- Charles _______________________________________________ Xplor-nih mailing list [email protected] https://dcb.cit.nih.gov/mailman/listinfo/xplor-nih
