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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

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.

Education

B.S. 1966 University of Chicago
Ph.D. 1971 Columbia University
(Attended Albert Einstein College of Medicine in the M.D.-Ph.D. program, 1967-1968)
Postdoc. 1971-1973 with Dr. Jack Strominger, Harvard University

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

Professor Emeritus, Biochemistry

Highlighted Publications

Representative Publications

Chang, H. Y., Choi, S. K., Vakkasoglu, A. S., Chen, Y., Hemp, J., Fee, J. A., and Gennis, R. B. (2012) Exploring the proton pump and exit pathway for pumped protons in cytochrome ba3 from Thermus thermophilus, Proc Natl Acad Sci U S A 109, 5259-5264.

Lin, M. T., Baldansuren, A., Hart, R., Samoilova, R. I., Narasimhulu, K. V., Yap, L. L., Choi, S. K., O'Malley, P. J., Gennis, R. B., and Dikanov, S. A. (2012) Interactions of Intermediate Semiquinone with Surrounding Protein Residues at the Q(H) Site of Wild-Type and D75H Mutant Cytochrome bo(3) from Escherichia coli, Biochemistry 51, 3827-3838.

Lin, M. T., and Gennis, R. B. (2012) Product-controlled steady-state kinetics between cytochrome aa(3) from Rhodobacter sphaeroides and equine ferrocytochrome c analyzed by a novel spectrophotometric approach, Biochim Biophys Acta. 1817, 1894-1900.

Yildiz, A. A., Knoll, W., Gennis, R. B., and Sinner, E. K. (2012) Cell-free synthesis of cytochrome bo(3) ubiquinol oxidase in artificial membranes, Analytical biochemistry 423, 39-45.

von Ballmoos, C., Adelroth, P., Gennis, R. B., and Brzezinski, P. (2012) Proton transfer in ba(3) cytochrome c oxidase from Thermus thermophilus, Biochim Biophys Acta 1817, 650-657.

Nasvik Ojemyr, L., von Ballmoos, C., Gennis, R. B., Sligar, S. G., and Brzezinski, P. (2012) Reconstitution of respiratory oxidases in membrane nanodiscs for investigation of proton-coupled electron transfer, FEBS Lett 586, 640-645.

Nowak, C., Laredo, T., Gebert, J., Lipkowski, J., Gennis, R. B., Ferguson-Miller, S., Knoll, W., and Naumann, R. L. (2011) 2D-SEIRA spectroscopy to highlight conformational changes of the cytochrome c oxidase induced by direct electron transfer, Metallomics 3, 619-627.

Tang, M., Sperling, L. J., Berthold, D. A., Schwieters, C. D., Nesbitt, A. E., Nieuwkoop, A. J., Gennis, R. B., and Rienstra, C. M. (2011) High-resolution membrane protein structure by joint calculations with solid-state NMR and X-ray experimental data, J Biomol NMR 51, 227-233.

von Ballmoos, C., Gennis, R. B., Adelroth, P., and Brzezinski, P. (2011) Kinetic design of the respiratory oxidases, Proc Natl Acad Sci U S A 108, 11057-11062.

Borisov, V. B., Gennis, R. B., Hemp, J., and Verkhovsky, M. I. (2011) The cytochrome bd respiratory oxygen reductases, Biochim Biophys Acta 1807, 1398-1413.

Borisov, V. B., Murali, R., Verkhovskaya, M. L., Bloch, D. A., Han, H., Gennis, R. B., and Verkhovsky, M. I. (2011) Aerobic respiratory chain of Escherichia coli is not allowed to work in fully uncoupled mode, Proc Natl Acad Sci U S A 108, 17320-17324.

Egawa, T., Ganesan, K., Lin, M. T., Yu, M. A., Hosler, J. P., Yeh, S. R., Rousseau, D. L., and Gennis, R. B. (2011) Differential effects of glutamate-286 mutations in the aa(3)-type cytochrome c oxidase from Rhodobacter sphaeroides and the cytochrome bo(3) ubiquinol oxidase from Escherichia coli, Biochim Biophys Acta 1807, 1342-1348.

Han, H., Hemp, J., Pace, L. A., Ouyang, H., Ganesan, K., Roh, J. H., Daldal, F., Blanke, S. R., and Gennis, R. B. (2011) Adaptation of aerobic respiration to low O2 environments, Proc Natl Acad Sci U S A 108, 14109-14114.

Lee, H. J., Gennis, R. B., and Adelroth, P. (2011) Entrance of the proton pathway in cbb3-type heme-copper oxidases, Proc Natl Acad Sci U S A 108, 17661-17666.

Lin, M. T., Sperling, L. J., Frericks Schmidt, H. L., Tang, M., Samoilova, R. I., Kumasaka, T., Iwasaki, T., Dikanov, S. A., Rienstra, C. M., and Gennis, R. B. (2011) A rapid and robust method for selective isotope labeling of proteins, Methods 55, 370-378.

Recent Publications

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), [148907]. https://doi.org/10.1016/j.bbabio.2022.148907

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), [148433]. https://doi.org/10.1016/j.bbabio.2021.148433

Graf, S. S., Hong, S., Müller, P., Gennis, R., & von Ballmoos, C. (2021). Energy transfer between the nicotinamide nucleotide transhydrogenase and ATP synthase of Escherichia coli. Scientific reports, 11(1), [21234]. https://doi.org/10.1038/s41598-021-00651-6

Iwasaki, T., Miyajima-Nakano, Y., Fukazawa, R., Lin, M. T., Matsushita, S-I., Hagiuda, E., Taguchi, A. T., Dikanov, S. A., Oishi, Y., & Gennis, R. B. (2021). Escherichia coli amino acid auxotrophic expression host strains for investigating protein structure-function relationships. Journal of Biochemistry, 169(4), 387-394. https://doi.org/10.1093/jb/mvaa140

Jose, A., Schaefer, A. W., Roveda, A. C., Transue, W. J., Choi, S. K., Ding, Z., Gennis, R. B., & Solomon, E. I. (2021). The three-spin intermediate at the O–O cleavage and proton-pumping junction in heme–Cu oxidases. Science, 373(6560), 1225-1229. https://doi.org/10.1126/science.abh3209

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