Nuclear magnetic resonance as a quantitative tool to study interactions in biomacromolecules*
S. Grzesiek, M. Allan, F. Cordier, D. Häussinger, P. Jensen, J. Kahmann, S. Meier, and H. J. Sass
Biozentrum, University of Basel, CH 4056 Basel, Switzerland
Abstract: High-resolution nuclear magnetic resonance (NMR) has emerged as one of the most versatile tools for the quantitative study of structure, kinetics, and thermodynamics of biomolecules and their interactions at atomic resolution. Traditionally, nuclear Overhauser enhancements (NOEs) and chemical shift perturbation methods are used to determine molecular geometries and to identify contact surfaces, but more recently, weak anisotropic orientation, anisotropic diffusion, and scalar couplings across hydrogen bonds provide additional information.
Examples of such technologies are shown as applied to the quantitative characterization of function and thermodynamics of several biomacromolecules. In particular, (1) the structural and dynamical changes of the TipA multidrug resistance protein are followed upon antibiotic binding, (2) the trimer-monomer equilibrium and thermal unfolding of foldon, a small and very efficient trimerization domain of the T4 phagehead, is described in atomic detail, and (3) the changes of individual protein hydrogen bonds during thermal unfolding are quantitatively followed by scalar couplings across hydrogen bonds.
Keywords: Biomacromolecules; biomolecular interactions; protein folding; thermal unfolding; hydrogen bonds; scalar coupling; anisotropic orientation; protein dynamics; TipA; foldon.
*Paper based on a presentation at the 18th IUPAC International Conference on Chemical Thermodynamics (ICCT-2004), 17-21 August 2004, Beijing, China. Other presentations are published in this issue, pp. 1297-1444.