Syntax

HBUIld { <hbuild-statement> } END

is invoked from the main level of X-PLOR. The END statement activates hydrogen building.

<hbuild-statement>:==

ACCEptor=<selection>

selects atoms that should be perceived as acceptors for hydrogen bonds involving waters (default: all atoms that have an explicit ACCEptor assignment; see Section 3.1.1).

CUTWater=<real>

specifies the cutoff value for acceptors involving hydrogen bonds to waters (default: 7.5 Å).

PHIStep=<real>

specifies the step size in degrees for the dihedral angle search in cases where the placement of the hydrogens is not unique (default: 10).

PRINt

is a flag that provides information about the partial energies during the local minimizations.

SELEction=<selection>

specifies a selection of atoms that should be built. Only hydrogens may be specified; hydrogens are defined in X-PLOR by their mass being less than 3.5 amu. An error statement will be returned if any of the selected atoms has a larger mass (default: (HYDRogen AND NOT KNOWn) ).