REDOR Applications in Biology: An Overview

Abstract

Rotational echo double resonance (REDOR) is a solid-state NMR technique that provides a direct measure of heteronuclear dipolar coupling typically between isolated pairs of labeled nuclei under magic angle spinning conditions. The couplings contain information on both distance and orientation; therefore REDOR can serve as a spectroscopic ruler and protractor in the study of molecular systems. In addition, it can be used as a spectroscopic selection tool to filter spectra based on dipolar couplings. Over the past 20 years, REDOR has been employed around the world to obtain site-specific atomic-level information on metabolic pathways, protein-ligand interactions, and in the analysis of noncrystalline, poorly soluble and heterogeneous molecular systems such as synthetic polymers, membrane proteins, intact plant leaves, and bacterial cells and cell walls. In this review, we provide a survey of recent applications to illustrate the problem-solving versatility of REDOR in biological systems. Keywords: REDOR; dipolar couplings; magic-angle spinning; CPMAS; whole-cell NMR; antimicrobial peptides; protein–protein interaction; membrane proteins