NMR Relaxation Dispersion Spectroscopy Analysis Software for Windows, Mac and Linux

NESSY banner
Home Download References Tutorial Manual Links Mailing List

Welcome to the webpage of NESSY.

NESSY is an open source software to analyse NMR relaxation dispersion data of either CPMG or R1p (R1rho) dispersion experiments. The graphical interface enables simple management of large experimental data sets and simple and automated analysis. NESSY autamatically calculates effective transverse relaxation rate (R2eff) and performs model selection between different relaxation dispersion models.


  • Calculation of effective transverse relaxation rate (R2eff)
  • Models for 1 - 9 exchanging states
  • Analysis of multiple data set (global fit)
  • Analysis of CPMG relaxation dispersion experiments
  • Analysis of R1rho spin lock relaxation dispersion experiments
  • Model-selection between different models
  • Akaike information criteria (AIC) model selection
  • F-test for model selection
  • Grid search for estimation of parameters
  • Chi2 curvefit and model selection
  • Levenberg-Marquardt algorithm (least squares curve fitting)
  • Monte Carlo simulations for estimation of uncertainities of extracted parameters
  • Extraction of exchange rate (Rex), exchange konstant (kex), population of exchanging states (pa, pb), chemical shift differences (dw)
  • Color and width coded structures (pdb)
  • Calculation of Free Energy
  • van't Hoff analysis (linear and non-linear model)
  • Transition state theory (using Eyring equation)
  • Hydrogen-Deuterium (H/D) exchange
  • 2D and 3D plotting
  • Creation of energy landcapes


  • NESSY runs on Windows, Mac and Linux operating systems
  • Written in Python for maximal performance
  • Import of peaklists:
    • Space or tabulator separated
    • Semicolon separated
    • CcpNmr
    • Sparky
    • XEASY
    • NMR View
    • any text file
  • Import of VD lists (Bruker)
  • Import of Bruker Protein Dynamics Center Project
  • PyMOL
  • Excell, OpenOffice...

Results generated by NESSY:

  • Plots in PNG, SVG, PS, EPS and PDF format (see following points)
  • Exchange konstant kex
  • Exchange rate Rex
  • Population of exchanging states (pa, pb)
  • Shift differences
  • Curvefit to different models
  • Model selection
  • CSV file of results for Excell, OpenOffice...
  • Colour coded structures (using PyMOL)


Windows 7 OSX 10.6 Ubuntu 11.04
Windows 7
OSX 10.6
Ubuntu 11.04


Automated NMR relaxation dispersion data analysis using NESSY, M. Bieri and P. Gooley, BMC Bioinformatics 2011, 12:421



ARC Rowden White Foundation
(C) Michael Bieri 2010