PARArestraints for Xplor-NIH is the complete set of modules which have been developed in order to use paramagnetism-based NMR restraints in protein structure calculations with the program Xplor-NIH. Paramagnetism-based restraints are paramagnetic relaxation enhancements, pseudocontact shifts, residual dipolar couplings due to metal and overall magnetic anisotropy, and cross-correlation between Curie relaxation and nuclear-nuclear dipolar relaxation.

User Manual:

Tutorial (.doc)
Tutorial (.pdf)

A patch has been created, to upgrade Xplor-NIH version 2.9.2 with the new modules:

Patch file
Readme file

You can also download the source files:


Here you can find two sample calculations (files updated on 02/03/2004):


When using PARArestraints for Xplor-NIH, please cite:

Banci L, Bertini I, Cavallaro G, Giachetti A, Luchinat C, Parigi G, 2004, "Paramagnetism-based restraints for Xplor-NIH", Journal of Biomolecular NMR 28: 249-61.