Jonathan Lukin
Department of Biological Sciences
 Carnegie Mellon University

 Wednesday, October 31, 2001
Willet Science Center 101

“NMR Studies of Biomolecules: a New Spin on Biology”

Abstract: The physiological functions of biological molecules such as DNA, RNA and proteins are directly related to the structural arrangement and dynamic motion of their constituent atoms.  These molecular properties can be investigated by high-resolution nuclear magnetic resonance (NMR) spectroscopy, which detects the response of nuclear spins to applied magnetic fields.  This talk will provide an overview of the rapidly advancing field of solution-state NMR, and its applications to the study of protein structure and dynamics.  An introductory description of protein structure will be given, together with remarks on the relationship between structure and function in biological macromolecules.  Next, the physical basis of NMR, and the information provided by pulsed NMR experiments will be reviewed.  Different sequences of radio-frequency pulses, applied to isotopically-labeled molecules, reveal two types of correlations between nuclei.  The coupling of nuclear spins linked by chemical bonds is used to assign each resonance to the specific nucleus in the protein where it originates.  Then, the dipolar interaction of nearby spins can be interpreted as constraints on the distances between atoms.  These constraints are converted, by computational methods such as restrained molecular dynamics, to consistent three-dimensional structures.  Modern NMR techniques can provide protein structures of high resolution, comparable to those obtained by X-ray crystallography, with additional information on the protein's dynamic behavior under physiological conditions.

 Please join us for light refreshments at 4:15.