[phenixbb] increasing NCS restraints

Yarrow Madrona amadrona at uci.edu
Thu Oct 17 12:48:38 PDT 2013

I am doing restrained NCS refinement and would like to know how to set the
target weight of the cartesian restraint in the command line? I also found
a sigma value in the GUI. I read that I can decrease it in order to
increase the NCS restraints. However, I have seen this under Torsional
restraints. Does this also apply to cartesian restraints?

I am doing this so that I can look at the differences in position and
B-factors of two molecules in the ASU that I am trying to determine are
related by a perfect or imperfect 2(1) screw axis. (I posted a question
about this on the CCP4 bullitan board.) If the values between molecules
are exactly the same then presumably the space group is actually P212121
with 1molecule in the asu instead of P21 with two molecules. I already
know that the P21 dimer superimposes almost exactly on the P212121 monomer
and it's symmetry mate. I just don't know how "perfectly" they align and I
am hoping this approach will tell me. I hope this makes some sense.


Yarrow Madrona

Graduate Student
Molecular Biology and Biochemistry Dept.
University of California, Irvine
Natural Sciences I, Rm 2403
Irvine, CA 92697

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