Considerable diversity exists in the mechanisms of ion transport in living systems. This is basic research into one class of ion transport proteins that is widely distributed in the biosphere. Rnf is a widely distributed family of bacterial membrane proteins that is involved in a variety of important physiological processes, including nitrogen fixation, oxygen sensing and anaerobic metabolism. So far, all the members of this family seem to transport sodium ions across the bacterial cell membrane. Some Rnfs behave as redox-driven ion pumps contributing energy to the membrane potential, while others consume the gradient to drive unfavorable redox reactions. Moreover, the actual directionality of coupling between the redox reaction and ion translocation appears to vary in different Rnfs. For a class of enzymes with so many important roles, little is known about the structure or mechanism. The overall goal of this project is to define the physiological roles of the various Rnfs and understand the mechanisms that underpin these functions. Efforts will be focused on the identity of the pumped ion, the directionality of the pumping reaction, the topology of the enzyme and the localization of cofactors with respect to the membrane. This work will provide the basis for future studies on members of this family and will shed light of how similar proteins perform diverse functions. The project will use a combination of biophysical, kinetic and spectroscopic studies using site directed mutants to characterize the individual mechanistic steps in the enzyme reaction. This multidisciplinary approach will give an understanding of the functioning of this family of proteins in the context of the overall bacterial physiology.
Broader Impact This project will provide a foundation for the understanding of the mechanism of the Rnf family of proteins, a group of proteins widely distributed in bacteria. The combination of biochemistry, biophysical techniques will provide a better understanding of the mechanism of these enzymes, their physiological roles and eventually how bacteria achieve complicated reactions as nitrogen fixation, oxygen sensing and adaptation to different environments.
The PI is actively involved in graduate and undergraduate education and students at all levels participate in research efforts in the PI's laboratory. This project will include a strong commitment in training a graduate student and a postdoctoral trainee in the PI's lab. The multidisciplinary approach of the project will provide an excellent opportunity for the participants of this project to learn basic techniques in Microbiology, Biochemistry, Spectroscopy and Biophysics. The laboratory will host a summer student from the local High School in coordination with the 'Design your Future Day Program' which brings high school girls to visit RPI for a day.
