Current version: 3.2
Xplor-NIH is now based on Python3. This version is built using
Python3.7, and also validated using Python3.8 and Python 3.9 (where it produces
somewhat different output). Scripts in the eginput subdirectory have
been updated to work with Xplor-NIH version 3. Old user scripts should
be *mostly* compatible with the new version, the primary cause for
problems being the print statement, which is now a function requiring
should now be
New in this release:
XPLOR-NIH is a structure determination program which builds on the
program, including additional tools developed at
the NIH. These tools include functionality for the following:
- Further improvements to the eginput/PSF_generation/genLigandCif.py
script for generating topology and parameter input for small
- Added support for the following residue variants: SEP, TPO and
PTR to the standard Xplor-NIH force field.
- Generalized the coarse-grain representatiion facility
- NMR Exchange Format (NEF) support: added ability to handle
Added facility to auto-determine the
set of ordered residues used for final fitting in
- Many bug fixes, documentation improvements, optimizations and
other additions. Please see the
- 3J couplings
- 1J couplings
- 13C shifts
- 1H shifts
- dipolar couplings
- radius of gyration
- solution X-ray and neutron scattering
- refinement using paramagnetic relaxation enhancement spectroscopy
- conformational database torsion angle potentials
- database base-base positioning potentials for DNA
- interface to the NMR graphics package
- embedded Python and TCL interpreters.
- addition of Generalized Born code from Tom Simonson .
- support for computing swarms of structures in parallel using
- paramagnetic relaxation enhancement module (Python
interface) based on the modified Solomon-Bloembergen equation and
multiple structure representation for paramagnetic groups. This module
contributed by Junji Iwahara. Please contact him at
iwahara-at-helix.nih.gov(replace -at- with a @) for further information.
- The PASD/Marvin facility for automatic NOE assignment.
for including paramagnetism-based NMR restraints in refinement.
- the bin/seq2psf script to generate psf file from sequence.
- includes the isac code for floating RDC alignment tensor.
H.J. Sass, G. Musco, S.J. Stahl, P.T. Wingfield and S.Grzesiek,
J. Biomol. NMR 21: 275-280 (2001).
- merged hbdb code from A. Grishaev.
An empirical pseudo-potential that encodes for the relative
arrangement of two protein peptidyl units linked by a
backbone-backbone hydrogen bond.
- a new CSA potential in the Python interface.
- Removed arbitrary limits on all PSF parameters. Xplor-NIH startup
size has been reduced by about 25MB, and it will handle systems
as large as your computer's memory will allow.
XPLOR-NIH also includes an new internal variable module
(IVM) which allows one to perform efficient molecular dynamics and
minimizations using internal coordinates, such as torsion angles.
The IVM permits one to do
combined torsion angle/rigid body dynamics, torsion angle/cartesian
coordinate dynamics, etc. We have found that a 6th order
predictory-corrector integrator utilizing a time-varying, automatically
time step size provides large computational advantages over the other
X-PLOR dynamics engines.
Authors of the NIH extensions:
G. Marius Clore
, Guillermo Bermejo,
, John Kuszewski,
Charles D. Schwieters, and
When publishing work which utilizes Xplor-NIH, please cite:
C.D. Schwieters, J.J. Kuszewski, N. Tjandra and G.M. Clore,
"The Xplor-NIH NMR Molecular Structure Determination Package,"
J. Magn. Res., 160, 66-74 (2003).
C.D. Schwieters, J.J. Kuszewski, and G.M. Clore, "Using
Xplor-NIH for NMR molecular structure determination,"
Progr. NMR Spectroscopy 48, 47-62 (2006).
Other relevant references are listed
. Please cite all appropriate references.
Please see the documentation page.
Here is a frequently asked questions page:
For questions about this package, please use the
mailing list by sending a message to
of answered questions can be found
To download XPLOR-NIH binary packages or source code, please click
. Instructions for installation of these packages can be found
The following are available:
To be notified when new versions of XPLOR-NIH are released, subscribe
- executables for multiple Unix platforms.
- various useful parameter and topology files for proteins, dna
and dipolar couplings.
- the various databases.
- some examples using most of the refinement tools, IVM torsion
angle dynamics, etc. Additional examples are available
To obtain the source code of XPLOR-NIH please contact either
Charles Schwieters (Charles.Schwieters@nih.gov)
Marius Clore (email@example.com)
Tools for use at NIH.
National Institutes of Health
Department of Health and Human Services