NS CPMG 2-site expanded

Intro

The relaxation dispersion model for the numeric solution (NS) to the Bloch-McConnell equations for SQ CPMG-type data. This uses the Maple expanded and fast equations from Nikolai Skrynnikov. The model is labelled as NS CPMG 2-site expanded in relax.

This type of model can be called silico derived, as it is a computer-assisted derivation for the equivalent computations, of the much more expensive numerical matrix-form.

This function is exact, just as the explicit Bloch-McConnell numerical treatments. It comes from a Maple derivation based on the Bloch-McConnell equations. It is much faster than the numerical Bloch-McConnell solution. It was derived by Nikolai Skrynnikov and is provided with his permission.

Parameters

The NS CPMG 2-site expanded model has the parameters {$R_2^0$, $...$, $p_A$, $\Delta\omega$, $k_{ex}$}.

Code

The library code.
http://svn.gna.org/viewcvs/*checkout*/relax/trunk/lib/dispersion/ns_cpmg_2site_expanded.py?revision=HEAD

Reference

The reference for the NS CPMG 2-site expanded model is:

• Tollinger, M., Skrynnikov, N. R., Mulder, F. A. A., Forman-Kay, J. D., and Kay, L. E. (2001). Slow dynamics in folded and unfolded states of an sh3 domain. J. Am. Chem. Soc., 123(46), 11341-11352. (10.1021/ja011300z).

Code origin

The code originates as optimization function number 5 from the fitting_main_kex.py script from Mathilde Lescanne, Paul Schanda, and Dominique Marion (see [1], [2] and [3]).

Links to the copyright licensing agreements from all authors are:

• Nikolai Skrynnikov,
• Martin Tollinger,
• Paul Schanda,
• Mathilde Lescanne,
• Dominique Marion.

Links

The implementation of the NS CPMG 2-site expanded model in relax can be seen in the:

• relax manual,
• API documentation,
• relaxation dispersion page of the relax website.