If a multimer coordinate file exists, one has to split the coordinates of the multimer into several files, one for each protomer with disjoint segment names. The following shows an example for a trimeric structure (ignore the "multiple coordinates" error messages).
structure @protomer.psf vector do (segid="a") ( segid " " ) coordinates @a.pdb {* Read protomer a.*} duplicate segid="b" selection=( segid "a" ) end coordinates @b.pdb {* Read protomer b.*} duplicate segid="c" selection=( segid "a" ) end coordinates @c.pdb {* Read protomer c.*}Note that if using the NCS strict statement (Section 18.2.1), one has to create only one protomer structure.
If a protomer coordinate file exists and one knows the appropriate transformations between the monomers, one should read the monomer, use the duplicate statement to duplicate the molecular structure as well as the coordinates, and apply appropriate coordinate transformations (marked by ...in the example below) to produce the other monomers.
structure @protomer.psf coordinate @protomer.pdb vector do (segid="a") ( segid " " ) duplicate segid="b" selection=( segid "a" ) end coordinates rotate ... selection=( segid "b" end coordinates translate ... selection=( segid "b" ) end duplicate segid="c" selection=( segid "a" ) end coordinates rotate ... selection=( segid "c" end coordinates translate ... selection=( segid "c" ) end
Xplor-NIH 2024-09-13