Vibrations, Structure & Dynamics of Biomacromolecules

Strauss, Herbert

Abstract

The long term objective of this research is to provide effective vibrational-spectroscopic methods for determining the conformational structure and properties of complex biomolecules and, in particular, those of lipids in membrane bilayers and of polypeptides and proteins. The vital role of conformational isomerism in determining biological function and activity is well established for these systems. However, most methods currently available for analyzing spectra in terms of conformation have been developed for small molecules and are ineffective for the very large molecules of the kind that are biologically relevant. The focus of this work will be to find new quantitative ways to analyze the enormously complex infrared and Raman spectra of biomacromolecules. Specific topics for investigation include the following: (i) simplified computational methods for determining conformational statistics from the spectrum of a disordered system; (ii) numerical methods for determining ensemble-averaged descriptions of the modes of a conformationally disordered system and estimates of the degree of spacial localization of these modes; (iii) methods for interpreting in terms of structure a spectrum whose features consist of contours rather than individual bands; (iv) a computer program designed to aid nonspecialists to carry out normal coordinate calculations and also to promote the exchange of normal coordinate data; (v) studies on the conformational structure and dynamics of lipid bilayers, simple polypeptides in random conformations, and globular proteins; (vi) Raman spectroscopic studies of the low-frequency vibrations associated with long range, large amplitude, cooperative motion in bilayers, polypeptides, and proteins.