¹⁵N-{¹H} NOE experiment at high magnetic field strengths

Authors: Gong, Qingguo; Ishima, Rieko

Source: Journal of Biomolecular NMR, Volume 37, Number 2, February 2007 , pp. 147-157(11)

Publisher: Springer

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Abstract:

The heteronuclear ¹⁵N-{¹H} NOE values are typically determined by taking the ratio of ¹⁵N signal intensities recorded in the presence and absence of ¹H saturation prior to evolution of ¹⁵N magnetization. Since the intensity ratio of two independent experiments is taken, complete recovery of ¹⁵N magnetization during the scan repetition delay is critical to obtain reliable NOE values. Because it may not be practical to wait for the complete recovery of magnetization at high magnetic fields, Solomon equations may be used to correct measured NOE values. Here, based on experiments and simulations, we show that since the cross-correlation between ¹H-¹⁵N dipole and ¹⁵N chemical shift anisotropy becomes significant at high fields for small or deuterated proteins, measured NOE values can not be accurately corrected based on the Solomon equations. We also discuss ranges of rotational correlation times and proton spin-flip rate, in which the NOE values can be corrected by the equations.

Keywords: Cross-relaxation; Cross-correlation; Protein; Dynamics; Relaxation; NMR

Document Type: Research article

DOI: http://dx.doi.org/10.1007/s10858-006-9125-7

Affiliations: 1: Email: ishima@pitt.edu

Publication date: 2007-02-01