Well - I would begin by submitting both sets of coordinates to pisa which will attempt to group the NCS into the "best" complex.
Once you have that you can use any of the SUPERPOSE options to fit A to B, A to C , B to C etc. for each molecule and from that deduce your NCS class. eg: Hexamers - 6 fold rotations- teramers - 2 2 2 symmetry etc etc.. Then SSM will probably fit the two different structures together and you can see where the differences are Eleanor On 19 June 2015 at 14:46, <[email protected]> wrote: > Dear Tobias, > > > > If you have coordinates available for the different space groups, the > obvious solution is to first generate complete NCS units in the different > space groups, using appropriate crystallographic symmetry and then > superimpose the whole unit with something like lsqkabs. You have to watch > out though, that equivalent molecules are used for the superposition. > > > > Best, > > Herman > > > > *Von:* CCP4 bulletin board [mailto:[email protected]] *Im Auftrag von > *Tobias Beck > *Gesendet:* Freitag, 19. Juni 2015 15:07 > *An:* [email protected] > *Betreff:* [ccp4bb] determine NCS operators from PDB coordinates > > > > Dear all, > > I have a PDB file that contains NCS in the asymmetric unit, probably point > group D3. > > 1.) What program is recommended for determining the symmetry operators > from PDB coordinates? I found findncs, but this uses only heavy atom > coordinates (I could probably use just the sulfurs from the PDB as a work > around). > > 2.) Then I would like to compare the PDB file to a related structure. Here > I would like to align the symmetry operators determined above with symmetry > elements found in a different space group, for example align the twofold > axis from NCS with a twofold axis in found in a particular space group. > > What is a good way to go about this? > > I am aware that NCS is used in programs as restraints during refinement, > but here I am interested in obtaining the NCS symmetry operators and > aligning them to symmetry elements present in a new space group. Maybe I am > overlooking an obvious solution. > > Any help is greatly appreciated. > > Thanks and best wishes, Tobias. > > -- > > ___________________________________________ > > Dr. Tobias Beck > - independent group leader - > RWTH Aachen University > Institute of Inorganic Chemistry > Landoltweg 1, office: 304N > 52056 Aachen, Germany > phone: +49-241-80-90057 > fax: +49-241-80-99003 > web: http://www.ac.rwth-aachen.de/extern/beck/ > ___________________________________________ >
