6CYANA: grid fragment - CYANA command

Parameters: selection=<string>             (default: <blank>)
            none

Defines a fragment to be analyzed by a subsequent grid search. The
angle selection must select a connected subset of the dihedral
angles. Alternatively, the option 'none' can be given to undefine
the current fragment. For instance,

  grid fragment "PSI 7 + PHI PSI CHI1 8 + PHI 9"

defines a molecular fragment comprising the PSI angle of residue 7, the
PHI, PSI and CHI1 angle of residue 8, and the PHI angle of residue 9.
