Magic-angle-sample-spinning NMR difference spectroscopy

Abstract

Magic-angle-sample-spinning (MASS) NMR difference spectra can be used to selectively observe the contribution of an isotopic label to the total NMR spectrum. Because the natural abundance background is removed, the measurement of centerband and sideband intensities, and therefore chemical-shift anisotropies, is facilitated. This is illustrated with difference spectra between native and specifically labeled bacteriorhodopsin. A device which permits precise setting and regulation of the spinning speed is required for these experiments and is described herein. The apparatus should also be useful in other MASS experiments where knowledge and regulation of the spinning speed is required. © 1988.