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Robert B. Gennis

Profile picture for Robert B. Gennis

Contact Information

Department of Chemistry
University of Illinois
A320 CLSL, Box 2-6
600 South Mathews Avenue
Urbana, IL 61801
Professor Emeritus of Chemistry, Professor Emeritus of Biochemistry

Biography

Professor Robert B. Gennis received his undergraduate degree from the University of Chicago in 1966 and his Ph.D. from Columbia in 1971. Professor Gennis' research interests are in biochemistry and biophysical chemistry.

Research Interests

protein-lipid interactions; membrane-bound enzymes; bioenergetics; cytochromes; structure and function of membrane proteins; mechanism of proton pumping by respiratory oxygen reductases; enzymology; bioenergetics

Research Description

Our laboratory is primarily engaged in studying membrane-bound metalloproteins that catalyze electron transfer reactions coupled to the generation of both a voltage and ion gradient across the membrane bilayer. Our goal is to determine the catalytic mechanisms and, in particular, the way by which these enzymes generate an electrochemical potential gradient across the membrane. Among the enzymes on which we are working are the respiratory oxidases from Escherichia coli and from Rhodobacter sphaeroides. The proton electrochemical gradients generated by these enzymes are used by the bacteria to provide the energy for active uptake of solutes and for the synthesis of ATP. In addition we are studying the sodium pumping respiratory NADH:ubiquinone oxidoreductase from Vibrio cholerae. This organism uses a sodium electrochemical gradient generated by this enzyme to drive a number of energy requiring processes, such as flagellar rotation required for cell motility. Generally, our research centers around how redox chemistry is coupled to moving ions (protons or sodium) across a membrane.

Techniques we use include classical preparative biochemistry, immunology, genetics, molecular biology, and biophysical methods such as FTIR spectroscopy, electrochemistry and rapid kinetics. In the E. coli system, our efforts are directed at the two terminal oxidases: cytochrome bo3 and cytochrome bd. Both of these enzymes oxidize ubiquinol in the cytoplasmic membrane and reduce O2 to H2O. Both generate a transmembrane voltage during enzyme turnover. Whereas the active site of the heme-copper oxidases contains a heme and a copper atom, the corresponding site in the bd-type oxidases contains two hemes.

Cytochrome bo3 is a member of the heme-copper superfamily of respiratory oxidases and is closely related to the mitocondrial cytochrome oxidase. The aa3-type and the cbb3-type cytochrome c oxidases from Rhodobacter sphaeroides are also members of the heme-copper oxidase superfamily. These enzymes are proton pumps, coupling the oxygen chemistry catalyzed at the active site to the electrogenic movement of protons across the membrane. We are particularly interested in determining the way in which protons are transferred within these heme-copper oxidases and the mechanism by which the proton pump operates. The X-ray structure of cytochrome oxidase provides a framework for extensive structure/function studies. We have identified two functionally important proton-conducting pathways.

Awards and Honors

Fellow, American Association for the Advancement of Science
Fellow, Biophysical Society
NIH Merit Award
NIH Research Career Development Award
Alfred P. Sloan Fellowship
Guggenheim Fellowship
Fulbright Scholar

Additional Campus Affiliations

J. Woodland Hastings Chair Emeritus, Biochemistry
Professor Emeritus, Biochemistry

Honors & Awards

Fellow, American Association for the Advancement of Science
Fellow, Biophysical Society
NIH Merit Award
NIH Research Career Development Award
Alfred P. Sloan Fellowship
Guggenheim Fellowship
Fulbright Scholar

Recent Publications

Murali, R., Pace, L. A., Sanford, R. A., Ward, L. M., Lynes, M. M., Hatzenpichler, R., Lingappa, U. F., Fischer, W. W., Gennis, R. B., & Hemp, J. (2024). Diversity and evolution of nitric oxide reduction in bacteria and archaea. Proceedings of the National Academy of Sciences of the United States of America, 121(26), Article e2316422121. https://doi.org/10.1073/pnas.2316422121

Wikström, M., Gennis, R. B., & Rich, P. R. (2023). Structures of the intermediates in the catalytic cycle of mitochondrial cytochrome c oxidase. Biochimica et Biophysica Acta - Bioenergetics, 1864(2), Article 148933. https://doi.org/10.1016/j.bbabio.2022.148933

Murali, R., Hemp, J., & Gennis, R. B. (2022). Evolution of quinol oxidation within the heme‑copper oxidoreductase superfamily. Biochimica et Biophysica Acta - Bioenergetics, 1863(8), Article 148907. https://doi.org/10.1016/j.bbabio.2022.148907

Zöller, J., Hong, S., Eisinger, M. L., Anderson, M., Radloff, M., Desch, K., Gennis, R., & Langer, J. D. (2022). Ligand binding and conformational dynamics of the E. coli nicotinamide nucleotide transhydrogenase revealed by hydrogen/deuterium exchange mass spectrometry. Computational and Structural Biotechnology Journal, 20, 5430-5439. https://doi.org/10.1016/j.csbj.2022.09.036

Fedotovskaya, O., Albertsson, I., Nordlund, G., Hong, S., Gennis, R. B., Brzezinski, P., & Ädelroth, P. (2021). Identification of a cytochrome bc1-aa3 supercomplex in Rhodobacter sphaeroides. Biochimica et Biophysica Acta - Bioenergetics, 1862(8), Article 148433. https://doi.org/10.1016/j.bbabio.2021.148433

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