Radius of Gyration Restraints
A pseudopotential for the radius of gyration allows a restraint for
the overall size of a group of atoms. The radius of gyration is
defined as
![\begin{displaymath}
\ensuremath{R_{\mbox{\scriptsize {gyr}}}}= \left[ <(r-<r>)^2> \right]^{1/2},
\end{displaymath}](img752.png) |
(26.1) |
where
is atom position, and
denotes average over all atoms.
The expected value for this quantity has been emprically determined to be
![\begin{displaymath}
\ensuremath{R_{\mbox{\scriptsize {gyr}}}}= 2.2 \ensuremath{N_{\mbox{\scriptsize {res}}}}^{0.38},
\end{displaymath}](img754.png) |
(26.2) |
where
is the number of residues in a compact globular region.
In the case of elongated structures, residues can be selected in
regional groupings for this restraint. The reference is
Kuszewski, Gronenborn, and Clore (1999).
Subsections
Xplor-NIH 2024-06-11