Syntax

NCS RESTraints { $<$NCS-restraints-statement$>$ } END

is invoked from the main level of X-PLOR.

$<$NCS-restraints-statement$>$:==

GROUp

{ $<$ncs-restraints-group-statement$>$ } END adds a new group to the restraint NCS database.

INITialize

erases the current restraint NCS database. If no restraints are specified, the energy flag NCS should be turned off as well.

$<$NCS-restraints-group-statement$>$:==

EQUIvalence=$<$selection$>$

adds a new set of NCS-equivalent atoms within the group to the restraint NCS database.

SIGB=$<$real$>$

gives the target deviation ${\sigma}_{ncs}$ for B-factor restraints (deviation from the average B of equivalent atoms) in Å$^2$ (default=2.0 Å$^{2}$).

WEIGht=$<$real$>$

gives the effective energy constant for the positional restraints in kcal mole$^{-1}$ Å$^{-2}$ (default: 300.0 kcal mole$^{-1}$ Å$^{-2}$).