DASHA

The software Dasha is designed for the model-free analysis for NMR relaxation data. Dasha can be used as an optimisation engine to replace the minimisation algorithms implemented within relax.

Website

The original Dasha website is http://www.nmr.ru/dasha.html (and archived on the Internet Archive).

Overview

From the Dasha homepage:

DASHA is an interactive program designed to investigate dynamics of biomolecules, for which data of 15N or 13C heteronuclear relaxation are available from NMR measurements. A number of sets of longitudinal and transverse relaxation rates of 15N or 13C nuclei and 1H-15N, 13C NOE's obtained at various NMR spectrometer frequencies might be used as the input. The measured longitudinal, transverse relaxation rates and NOE values are interpreted using the model-free approach of Lipari and Szabo (1982, J. Am. Chem. Soc., 104, 4546-4559). In addition to the overall rotational correlation time of the molecule, the internal dynamics of backbone N-H or C-H vectors of two types of internal motions - fast, on a time scale of <20 ps, and intermediate, close to 1 ns could be evaluated by constructing correspondent spectral density functions. Contribution of the conformational exchange to transverse relaxation rates of individual nitrogens or carbons could be elucidated using a set of different rates of the CPMG spin-lock pulse train in measuring T2 relaxation times (Orekhov et al., 1994, Eur. J. Biochem., 219, 887-896). Separate module DIFFC, included into the DASHA software, performs hydrodynamic calculations for proteins with known spatial structure. All input and output data could be easily presented in PostScript format.

Authors

• Vladislav Yu. Orekhov
• Dmitry M. Korzhnev
• Dmitry E. Nolde
• Alexander P. Golovanov
• Alexander S. Arseniev.

Version

The last release was 3.48c in May 2000.