Projects / relax


relax is a program designed for the study of the dynamics of proteins and other macromolecules though the analysis of experimental NMR data. It supports exponential curve fitting for the calculation of the R1 and R2 relaxation rates, calculation of the NOE, reduced spectral density mapping, the Lipari and Szabo model-free analysis, study of domain motions via the N-state model (or ensemble analysis) and frame order dynamics theories using anisotropic NMR parameters such as RDCs and PCSs, the investigation of stereochemistry in dynamic ensembles, and the analysis of relaxation dispersion.

Operating Systems

Recent releases

  •  05 Jun 2014 15:08

    Release Notes: This is a major feature and bugfix release which includes a large speed up of all analytic relaxation dispersion models, the correct handling of edge case failures in all models of the dispersion analysis, a number of fixes for the handling of list-type data in the GUI user function windows including the fatal GUI crashes on Mac OS X systems, and many other bug fixes. All users of the dispersion analysis, the relax GUI, or Mac OS X systems are recommended to upgrade to this newest version.

    •  23 May 2014 15:00

      Release Notes: This is a major bugfix release which includes the equations for the "B14" and "B14 full" relaxation dispersion models, from Baldwin 2014 and introduced with relax version 3.2.0, now being calculated correctly, the 'NS CPMG 2-site expanded' model correctly handling edge cases where no exchange is expected, and the structure.delete user function correctly operating when multiple models are loaded into the data store.

      •  21 May 2014 12:21

        Release Notes: This major feature release includes the addition of the new "B14" and "B14 full" relaxation dispersion models (from Baldwin 2014), a complete rearrangement of the module layout of the specific analyses packages, a number of new user functions, documentation improvements (including the addition of a new chapter to the manual for the N-state model or ensemble analysis), and numerous of other features. This is also a major bugfix release, with numerous bug resolved. This includes an essential bugfix for the error calculation in the new relaxation dispersion analysis.

        •  17 Mar 2014 18:05

          Release Notes: This is a minor feature and bugfix release which includes improvements to the relaxation dispersion chapter of the manual and the addition of a new infrastructure for R1rho data handling in the dispersion analysis.

          •  28 Feb 2014 18:59

            Release Notes: Changes include a comprehensive tutorial added to the manual that shows the dispersion analysis in the GUI, improved PDB chain ID support, a new mode for running a relax script and then entering the prompt UI mode, multiple file reading by the spectrum.read_intensities user function, and improvements to the relaxation dispersion analysis. A number of major bugs in the dispersion analysis concerning different relaxation delay times for different experiments and for improved handling of the offset have also been fixed. A number of important GUI bugs have also been fixed.


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