CAREER: Integrated Structural Biology Approach to Building Atomic Models Of Actin Complexes

University Of North Carolina At Charlotte, Charlotte NC

Investigators

Abstract

A cell is able to adopt different shapes and carry out coordinated, directed movements through its cytoskeleton, a dynamic network of actin filaments; these cellular activities are regulated by interactions between the cytoskeletal actin and numerous actin-binding proteins including the archetypal actin-binding protein, gelsolin. This research will probe the molecular interactions between actin and gelsolin utilizing a novel approach involving small-angle X-ray and neutron scattering (SANS) experiments. Small-angle scattering is ideal for studying the shape and conformation of macromolecular complexes (10 to 1000 kDa) in solution because the scattering is sensitive to internal electron (or in the case of neutrons, nuclear) density distribution, thus revealing the size and shape of the scattering molecule. In SANS, the contrast of individual components within the macromolecular complex can be manipulated systematically. This unique technique offers the only available method for extracting structural information on each protein within a composite of interacting proteins under near physiological conditions. Using molecular boundary information determined from neutron scattering experiments on gelsolin:actin complexes, well-constrained structural models of resultant large macromolecular complexes will be built by integrating all available biophysical information. Broader Impact: Next-generation neutron scattering capabilities can provide answers to important issues in the biological sciences. While the facilities necessary for conducting these types of experiments exist or are planned, many biological scientists who might benefit from this research infrastructure have only limited experience with neutron scattering instrumentation and techniques. This project details an educational plan to introduce the practical aspects of using neutron scattering and contrast variation technologies to provide a structural framework for modeling the detailed interactions of complex biological systems. The broader impact of this project will be to develop, educate and increase the user base of national neutron research centers.