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Next: Plane Restraints Up: Harmonic Coordinate Restraints Previous: Harmonic Coordinate Restraints


Point Restraints

X-PLOR provides a means to restrain the main coordinate set ( atom properties x,y,z) to the reference coordinate set (atom properties refx, refy, refz). The restraints are defined as
\begin{displaymath} E_{HARM}= \sum_{atoms} h_i (r_i - r_i^{ref})^{e} \end{displaymath} (7.1)

where the sum extends over all atoms, $h_i$ is individual weights, $r_i$ is the atomic coordinates of the main set, $r_i^{ref}$ is the atomic coordinates of the reference set, and $e$ is an exponent. The individual weights $h_i$ correspond to the atom property HARM and can be assigned using the vector statement (Section 2.16); the physical dimension of HARM is kcal mole$^{-1}$ Å$^e$. By default, $h_i$ is zero. The reference coordinate set can be assigned using the vector statement or by using the DISPosition option of the coordinate statement. The exponent $e$ is set by using the restraints harmonic statement.


Xplor-NIH 2025-03-21