This proposal requests funds to permit Dr. Gerald L. Hazelbauer, Department of Biochemistry/Biophysics, Washington State University, to pursue with Dr. Chankyu Park, Department of Biological Science and Engineering, Korea Advanced Institute of Science and Technology, for a period of 24 months, a program of cooperative research on the structure and function of chemoreceptor proteins. The general aim of this research is to contribute to an understanding of the mechanisms involved in the functioning of transmembrane receptor proteins. A basic feature of living cells is the ability to respond to specific, external chemical signals. The bacterium, Escherichia coli, contains specific receptors, exposed on the cell surface, that recognize relevant compounds. These bacteria are chemotactic as the result of the functioning of a multicomponent, sensory response system that links receptors to flagella. Understanding the mechanisms by which any of these receptors functions requires an understanding of how ligand binding or covalent modification at one place on a protein can affect activity of a domain separated from that site, how alterations at different sites on a protein can interact cooperatively or antagonistically, and how information is passed across a membrane. The present project involves a study of bacterial chemoreceptor proteins, called transducers. Genetic approaches involving isolation of mutants defective in one or a subset of transducer functions will be combined with biochemical approaches involving the characterization of mutant proteins in vivo as well as in vitro in a detergent-stabilized, purified state. This project is relevant to the objectives of the U.S.-Korea Cooperative Science Program which seeks to increase the level of cooperation between U.S. and Korean scientists and engineers through the exchange of scientific information, ideas, skills, and techniques and through collaboration on problems of mutual benefit.
