Robert P. Gunsalus, Ph.D.

Professor Emeritus and Distinguished Research Professor

(310) 206-8201

1602 Molecular Science Building


Microbial Cell Metabolism in Bacteria and Archaea


Professor Emeritus and Distinguished Research Professor,

Department of Microbiology, Immunology & Molecular Genetics

Faculty Member:

    The UCLA DOE Institute

    The UCLA Molecular Biology Institute

UCLA Graduate Programs in Biosciences (GPB) Home Areas:

   Immunity, Microbes & Molecular Pathogenesis GPB

   Genetics & Genomics GPB

   Biochemistry, Biophysics & Structural Biology GPB

Research Interests :

Our current research focuses on the molecular biology and physiology of anaerobic microorganisms including the syntrophic bacteria, their associated methanogenic partners plus other archaeal species. These microbes colonize a wide range of habitats on Earth and possess the ability to adapt and grow over a wide range of environmental conditions (e.g., substrate type, temperature, pH, salinity). We are examining how their metabolism, energy harvesting and associated cell envelope structures adapt to these changes using a variety of genetic, molecular and biochemical approaches.

1) Genomics and Proteomics of Syntrophic Bacteria.  The syntrophic bacteria along with their methanogenic archaeal partners are expert in the anaerobic recycling of biomass in marine and fresh water environments.  However, we know relatively little about their metabolism, cell structures or their ability to adapt to changing conditions. Using genomic, transcriptomic and proteomic tools we are elucidating core metabolic pathways for carbon utilization and energy harvesting in model syntrophic microorganisms plus their methanogenic community partners. The longer-term goal is to generate predictive metabolic models that describe these co-operative partnerships between the syntrophic bacteria and methanogenic archaea.

                             Metabolic reconstruction of Syntrophomonas wolfei


2) Structure and Function of Microbial Cell Envelopes. We are studying the composition, structure and function of microbial cell envelopes of representative archaeal and bacterial species.  Cell envelopes may contain a protein coat or surface layer that surrounds the cell membrane that aids in protecting it from environmental challenges. We have isolated and characterized the cell envelopes of representative archaeal methanogenic strains of the genus Methanosarcina. The major envelope proteins were identified and where many were previously annotated to be “hypothetical proteins”. The most abundant envelope proteins in three of these strains, M. mazei, M.acetivorans and M. barkeri, were structurally characterized. Following cytoplasmic synthesis, each protein is post-translationally modified and then exported to the cell surface where they are assembled into an outermost cell envelope layer. This coat surrounds and protects the cytoplasmic membrane.  The first high resolution three-dimensional structure of one of these archaeal S-layer proteins was recently obtained. These structure and function studies along with associated cell appendages (flagella and pili) provide insight regarding the ability of these archaea cell types to adapt to diverse growth conditions.

Methanospirillium hungatei cells and flagellum



Dr. Gunsalus is currently a Distinguished Research Professor in the Department of Microbiology, Immunology, and Molecular Genetics at the University of California, Los Angeles within the Schools of Life Sciences and Medicine. He obtained B.S. degrees is in Microbiology and in Chemistry from the South Dakota State University and went on to do his PhD studies in Microbial Biochemistry at the University of Illinois at Urbana Champaign working with Dr. Ralph S. Wolfe. Prior to joining the faculty at UCLA, he did postdoctoral work at Stanford University in Palo Alto in the areas of Molecular Biology with Dr. Charles Yanofsky and Dr. Robert D. Simoni.


James, K.L., Kung, J.W., Crable, R.R., Mouttaki, M., Sieber, J.R., Nguyen, H.H., Yang, Y., Xie, Y., Erde, J., Wofford, N.Q., Karr, E.A., Loo, J.A., Ogorzalek Loo, R.R., Gunsalus, R.P. and M.J. McInerney. 2019. Syntrophus aciditrophicus uses the same enzymes in a reversible manner to degrade and synthesize aromatic and alicyclic acids. Environmental Microbiology. 21:1833-1846.

Lauren E. Cook, L.E., S. Gang, A. Ihlan, M. Maune, R.S. Tanner, M.J. McInerney, G. Weinstock, E.A. Lobos and R.P. Gunsalus. 2018. Genome sequence of Acetomicrobium hydrogeniformans OS1. Genome Announc. 2018 Jun; 6(26): e00581-18. Published online 2018 Jun 28. doi:  10.1128/genomeA.00581-18

Briege, A., C.M. Oikonomou, Y-W Chang, Kjaer,A., A.N. Huang, K.W. Kim, D. Ghosal, D. Kenney, R.O.O. Loo, R.P. Gunsalus, and Grant J. Jensen. 2017. “Morphology of the archaellar motor and associated cytoplasmic cone in Thermococcus kodakaraensis. EMBO Rep. Sep;18(9):1660-1670.

Poweleit, N., P. Ge, H.H. Nguyen, R.R. Ogorzalek Loo, R. Gunsalus, and Z.H. Zhou. CryoEM structure of the Methanospirillum hungatei archaellum reveals structural features distinct from the bacterial flagellum and type IV pilus. Nature Microbiology. 2016. 2: 16264.

Gunsalus, R.P., L.E. Cook, B. Crable, L. Rohlin, E. McDonald, H. Mouttaki, J.R. Sieber, N. Poweleit, Z.H. Zhou, A.L. Lapidus H.E. Daligault, M. Land, P. Gilna, N. Ivanova, N. Kyrpides, D.E. Culley and M.J. McInerney. Complete genome sequence of Methanospirillum hungatei type strain JF1. Standards in Genomic Sciences. 2016; 11: 2.

Toso D.B, M.J. Javed, E. Czornyj, R.P. Gunsalus, and Z.H. Zhou. Discovery and Characterization of Iron Sulfide and Polyphosphate Bodies Coexisting in Archaeoglobus fulgidus Cells. Archaea. 2016. 2016: 4706532.

Arbing, M.A., S. Chan, A. Shin, T. Phan, C.J. Ahn, L. Rohlin, and R.P. Gunsalus. Structure of the surface layer of the methanogenic archaean Methanosarcina acetivorans. Proceedings of the National Academy of Sciences of the United States of America. 2012; 109: 11812-7.

Sieber, J.R. M.J. McInerney and R.P. Gunsalus. Genomic Insights into Syntrophy: The Paradigm for Anaerobic Metabolic Cooperation. Annual Review of Microbiology. 2012. 109(29): 429-452.

McInerney, M.J. L. Rohlin, H. Mouttaki, U.M. Kim. R.S. Krupp, L. Rios-Hernandez, J.R. Sieber, C.G. Struchtemeyer, A. Bhattacharyya, J.W. Campbell, and R.P. Gunsalus. The genome of Syntrophus aciditrophicus: life at the thermodynamic limit of microbial growth. Proceedings of the National Academy of Sciences of the United States of America. 2007; 104: 7600-5.

Lab Members:

  Shichun Ma, – Visiting Professor

  Erin Natalie – Research Assistant

  Shirley Zhang – Undergraduate Researcher

  Derek Lam – Undergraduate Researcher

  Megan Chu– Undergraduate Researcher


UCLA Molecular Biology Institute

UCLA DOE Institute of Genomics and Proteomics

UCLA Medical School Biosciences

EcoCyc – the Escherichia coli protein gene database

Departmental Graduate Studies in Microbiology


Dr. Robert Gunsalus

Department of Microbiology, Immunology, and Molecular Genetics
609 Charles E Young Dr S
1602 Molecular Science Building
Los Angeles, CA 90095
(310) 206-8201 office