6CYANA: angles flip - CYANA command

Parameters: selection=<string>             (default: <blank>)

The 'angles flip' command can be used to optimally flip torsion
angles that have two equivalent positions differing by 180 degrees
in a group on conformers. Such flipping is useful, for instance,
when calculating RMSD values. In polypeptides this applies mainly to
the aromatic rings of Phe and Tyr (CHI2), and to the side-chain COO-
groups of Asp (CHI2) and Glu (CHI3).

Torsion angles that match the selection <string> are changed by 180
degrees, if necessary to attain the smallest possible deviation from a
common average value within the selected conformers. By default, the
selection made in the most recent 'angles select' command is used,
or all angles if no selection has been made so far. Flipping will
occur only for those selected torsion angles that have two equivalent
positions differing by 180 degrees.

The 'flip.cya' macro provides a convenient interface for appying this
command to proteins.

See also: flip
