Current version: 3.2
Download. Documentation. FAQ. Support. Training.

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 parentheses. So print "value" should now be print("value") .

New in this release:

XPLOR-NIH is a structure determination program which builds on the X-PLOR program, including additional tools developed at the NIH. These tools include functionality for the following:

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 Nico Tjandra

When publishing work which utilizes Xplor-NIH, please cite:

Other relevant references are listed here . Please cite all appropriate references.


Please see the documentation page. Here is a frequently asked questions page: FAQ.


For questions about this package, please use the Xplor-NIH mailing list by sending a message to xplor-nih@list.nih.gov. Archives of answered questions can be found here .


To download XPLOR-NIH binary packages or source code, please click here . Instructions for installation of these packages can be found here. The following are available: To be notified when new versions of XPLOR-NIH are released, subscribe to the Xplor-NIH-announce mailing list.

To obtain the source code of XPLOR-NIH please contact either

Charles Schwieters (Charles.Schwieters@nih.gov)
Marius Clore (mariusc@intra.niddk.nih.gov)

Tools for use at NIH.

DCB logo - link to Division of
				Computational Bioscience NIH logo - link to the National Institutes of Health National Institutes of Health HHS logo - link to U. S. Department of Health and Human Services Department of Health and Human Services