ATP-binding cassette (ABC) Transporters have vital roles in the physiology of living cells. The current grant will support efforts to apply structural and thermodynamic understanding to elucidate the biochemical function of a broadly-distributed set of soluble mechanoenzymes of unknown function that possess ABC motor domains homologous to those in ABC Transporters. These homologues encode a tandem pair of motor domains in a single polypeptide, leading to their designation as soluble tandem ABC proteins or stABC's. The stABC's cluster into 10 sub-families likely to mediate distinct biochemical functions, and members of 2-6 families occur in every fully sequenced genome. Techniques in bacterial genetics and proteomics will be applied, as informed by ongoing structural and enzymological studies of ABC proteins, to elucidate the biochemical role played by these proteins of known sequence but cryptic function. Thus, an interdisciplinary genetic-biochemical-structural approach will be used to elucidate biological function, which represents a vital research activity in the post-genome era.
Broader Impacts: The project will contribute to the educational and training activities. A course module treating protein structure from a thermodynamic perspective has been developed. The proposed research will be integrated into an undergraduate "project laboratory" course in which a genomics approach is taken to addressing a current research problem in the laboratory. The undergraduates use online bioinformatics tools to identify homologous proteins, which they clone, express, and purify in order to perform biophysical assays that address a central mechanistic question. The goal is to teach students how to use laboratory research, disciplined by critical thinking, to address conceptual questions about biological function and mechanism.
