Re: [phenixbb] ncs restraints

Hi Tim, If you start from nearly identical copies (due to previous refinement), in the absence of a strong signal from the data, it is expected that the copies remain fairly similar even if you increase the sigma / lower the weight. We just added a new feature to phenix.refine that could be useful to introduce differences between the NCS copies, guided by the model density through a new real-space refinement protocol: strategy=individual_sites_real_space plus real_space_refinement.mode=lockit. At your resolution it is turned on by default. I.e. to try it out all you need to do is get dev-602 or higher and run phenix.refine again. Only trouble, those installers aren't generally visible since there were some minor problems, but watch out for a new one soon. Ralf

From: Timothy Springer To: [email protected] Sent: Tue, December 7, 2010 7:31:44 PM Subject: [phenixbb] ncs restraints

Hi, I am using NCS restraints for 4 copies of a molecule at 3.05 Å. We are using the standard weights: coordinate_sigma = 0.05 b_factor_weight = 10 and the 4 molecules look identical. What are suggested values for looser restraints? One of my colleagues said that varying them did not make a difference- ncs was still very strict. Is there a way to make them less strict? Thanks, Timothy A. Springer, Ph.D.