The mechanism of genetic recombination in E. coli. will be investigated by focusing on the biochemical and physical properties of the purfied protein and nucleic acid components. The goal of this proposed research will be to develop a molecular understanding of how the various components of the recombinant system interact to produce recombinant DNA molecules. The initial stages of this work will focus on mechanistic and physical aspects of the recA protein and its interaction with nucleic acid substrates to attempt to understand how the formation of joint DNA molecules is catalyzed. The later aspects of this project will seek to understand how recA protein interacts with other recombinational protein (such as recBC, SSB, gyrase and helicase) and what the effect of this interaction is on the activity of these enzymes.