Use of 13C and 15N isotope labels for proton nuclear magnetic resonance and nuclear Overhauser effect. Structural and dynamic studies of larger proteins and nucleic acids.

This article reviews methods based on direct observation of proton NMR in macromolecules containing 13C or 15N labels. The resonances and Overhauser effects of protons attached to the labels can be edited or filtered from the remaining overlapping resonances. This leads to simplification of the spectra when labels are incorporated selectively. In 2D and related methods the label's chemical shift provides a second dimension which is useful for spectral differentiation and identification. The methods are useful for larger proteins and we describe our progress on studies of T4 lysozyme, mass 18.7 kD, in which we have already identified a large number of resonances.