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.

Details

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.

Reference

Orekhov, V. Y., Nolde, D. E., Golovanov, A. P., Korzhnev, D. M. and Arseniev, A. S. (1995). Processing of heteronuclear NMR relaxation data with the new software DASHA Appl. Magn. Reson., 9(4), 581-588. (DOI: 10.1007/bf03162365)

Usage in relax

To use DASHA within relax, the following user function are provided:

These allow DASHA to be used as a model-free optimisation within relax, replacing the built-in algorithms.