Robert P. Gunsalus

Department of Microbiology, Immunology, & Molecular Genetics
Molecular Biology Institute
UCLA-DOE Laboratory
Lab Members
Lab Photos

Research Interests:  Regulation of respiratory and carbon pathways in microorganisms

Selected Recent Publications:

Arbing, M.A. S. Chan, T. Phan, C.J. Ahn, A. Shin, L. Rohlin, and R.P. Gunsalus.  2012.  Structure of a Methanogenic Archaean Surface Layer.  Proc. Nat. Acad. Sci.  (Epub ahead of print)
PMID: 22753492

Sieber, J.R., M.J. McInerney, and R.P. Gunsalus.  2012.  Genomic Insights into Syntrophy: The Paradigm for Anaerobic Metabolic Cooperation.  An. Rev. Microbiol.  Vol 66. (Epub ahead of print)
PMID: 22803797

Rohlin, R., D.R. Francoleon, U.M. Kim, J.A. Loo, R.R. Ogorzalek Loo, and R.P. Gunsalus.  2012.  Identification of the major expressed S-layer and cell surface layer related proteins in the model methanogenic archaea, Methanosarcina barkeri fusaro and Methanosarcina acetivroans C2A.  Archaea Volume 2012, 873589  (Epub ahead of print)
PMID: 22666082

Kim G, Deepinder F, Morales W, Hwang L, Weitsman S, Chang C, Gunsalus R, Pimentel M.  2012.  Methanobrevibacter smithii is the predominant methanogen in patients with constipation predominant-IBS and methane on breath analysis.  Dig Dis Sci.  2012 May 10.  (Epub ahead of print).
PMID: 22573345

Toso, D.B., A-M. Henstra, R.P. Gunsalus, and Z.H. Zhou.  2011.  Structural, mass, and elemental analyses of storage granules in methanogenic archaeal cells.  Environmental Microbiology 9:2587-2599.
PMID: 21854518

Keseler, I., J. Collado-Vides, A. Santos-Zavaleta, M. Peralta-Gil, S. Gama-Castro, Socorro; L. Muñiz-Rascado, C. Bonavides-Martínez, S. Paley, M. Krummenacker, T. Altman, P. Kaipa, A. Spaulding, J. Pacheco, M. Latendresse, M. Sarker, A. Shearer, A. Mackie, I. Paulsen, R. Gunsalus, and Pl Karp.  2011.  EcoCyc: a comprehensive database of Escherichia coli biology.  NAR 2011 D583-90.
PMID: 21097882

McInerney, M.J., J.R. Sieber, and R.P. Gunsalus.  2011.  Microbial syntrophy: An emerging paradigm for biochemical cooperation in microbial ecosystems.  Microbe.  6:479-485.

Silber, J.R., D.R. Sims, C. Han, E. Kim, A. Lykidis, A.L., Lapidus, E. McDonald, L. Rohlin, D.E. Culley, R.P. Gunsalus, and M.J. McInerney.  2010.  The genome of Syntrophomonas wolfei: new insights into syntrophic metabolism and biohydrogen production.  Environ. Microbiol.  12:2289- 2301.
PMID: 20482737

Rohlin, L., and R.P. Gunsalus.  2010.  Carbon-dependent control of electron transfer and central carbon pathway genes for methane biosynthesis in the Archaean, Methanosarcina acetivorans strain C2A.  BMC Microbiology 10:62
PMID: 20178638

Chan, S., I. Giuroiu, I. Chernishof, J. Chiang, R.P. Gunsalus, M.A. Arbing, and L.J. Perry.  2010.  Apo and ligand bound-structures of ModA from the archaeon Methanosarcina acetivorans.  Acta Cryst.  66:242-250.
PMID: 20208152

McInerney, M.J., J.R. Sieber, and R.P. Gunsalus.  2009.  Syntrophy in Anaerobic Global Carbon Cycles.  Current Opinion in Biotechnology.  20:623-32.
PMID: 19897353

Lai, D., B. Lluncor, I. Schroeder, R.P. Gunsalus, J.C. Liao, and H. G. Monbouquette.  2009.  Reconstruction of the archaeal isoprenoid ether lipid biosynthesis pathway in Escherichia coli through digeranylgeranylglyceryl phosphate.  Metabolic Engineering 11:184-191.
PMID: 19558961

Francoleon, D.R., P. Boontheung, Y. Yang, U-M. Kim, P. Denny, J.A. Loo, R.P. Gunsalus, and R.R. Ogorzalek Loo.  2009.  S-layer, surface-accessible, and Concanavalin-A binding proteins of Methanosarcina acetivorans and Methanosarcina mazei.  J. Proteome Research.  8:1972-1982.
PMID: 19228054

Keseler, I., C. Bonavides-Martinez, J. Collado-Vides, S. Gama-Castro, R.P. Gunsalus, D. Johnson, M. Krummenacker, L. Nolan, S. Paley, I. Paulsen, M. Peralta-Gil, A. Santos-Zavaleta, A. Shearer, P. Karp.  2009.  EcoCyc: A comprehensive view of Escherichia coli biology.  NAR.  37: D464-D-470.
PMID: 18974181

McInerney, M.J., C.G. Struchtemeyer, J. Sieber, H. Mouttaki, A.J.M. Stams, B. Schink, L. Rohlin, and R.P. Gunsalus.  2008.  Physiology, ecology, phylogeny, and genomics of microorganisms capable of syntrophic metabolism. in, Incredible Anaerobes: From Physiology to Genomics to Fuels.  J. Wiegel, R. Maier, and M. Adams, Eds. Anal. N.Y. Acad. Sci.  1125:58-72. ISBN 1-57331-705-5
PMID: 18378587

Lab Members:

Robert GunsalusP.I.
Diana Azurdiagrad student
Votek Bartkowskigrad student
Unmi Kimgrad student
Nicole Poweleitgrad student
Andrea Riveragrad student
Housna Mouttakipostdoc
Lars Rohlinpostdoc
Henly Wangresearch assistant
Angela Leeresearch assistant
Erin McDonaldundergraduate
Tran Leundergraduate
Jenny Parkundergraduate

Click for lab photos

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Our research focuses on understanding the physiology and molecular biology of gene regulation in model bacteria and archaea.  Emphasis is on the central pathways for cell respiration and carbon flow in pure as well as in co-cultures.

1) Oxygen dependent gene regulation in Escherichia coli.  This model intestinal microorganism differentially synthesizes a number of respiratory enzymes that enable it to thrive under a variety of environmental conditions.  These enzymes include two alternative cytochrome oxidases, three distinct nitrate reductase enzymes, a nitrite reductase, a DMSO reductase, a TMAO reductase, and a fumarate reductase.  The synthesis of each enzyme is switched on/off at the transcriptional level due to the action of two regulatory protein switches called Fnr and ArcA/ArcB.  We are studying how each functions during anaerobic cell growth conditions to recognize and bind at their respective regulatory sites on the chromosome.  We are also extending the understanding of the anaerobic gene families using whole genome DNA arrays and bioinformatics tools.

2) Nitrate dependent gene control in Escherichia coli.  Four proteins named NarX, NarQ, NarL, and NarP comprise a novel two-component signal transduction system that regulates many of anaerobic respiratory and fermentation pathway genes in the cell.  In response to nitrate availability, the system ensures that genes for the nitrate and nitrite reductase enzymes are optimally expressed.  It also functions to repress expression of many of the alternative respiratory and fermentation pathway genes.  We are examining the molecular details of the signal reception process, and the associated signal transduction that results in formation of activated NarL-phosphate and NarP-phosphate.  These two DNA binding proteins then recognize and bind at their cognate regulatory sites on the chromosome to effect appropriate nitrate-dependent gene control.

3) Metal-dependent gene expression.  E. coli is an excellent model to understand how essential trace metals like molybdenum and iron are aquired by the cell when needed to synthesize functional respiratory enzymes.  Current research projects include the study of molybdate dependent gene expression by the molybdate-responsive ModE regulatory protein.  This DNA binding protein works in concert with the oxygen (Fnr) and nitrate (Nar) regulators described above to coordinate gene expression when these trace metals are needed for cell growth.

4) Regulation in the methanogenic Archaea.  The molecular biology, biochemistry, and physiology the Archaea remain poorly understood relative to Bacteria.  However, these microbes are believed to be among the most ancient on Earth and thus provide interesting clues about the biochemical and molecular events that occurred early in evolutionary time.  We are examining the molecular biology of cell adaptation to change in environment conditions (e.g., carbon supply, temperature, oxidative, and osmotic stress).  A global DNA microarray approach is being used to examine patterns of gene expression in the model archaean, Methanosarcina acetivorans.

5) Genomics of syntrophic bacteria.  We have recently begun examining the molecular biology of a poorly understood group of microbes known as the syntrophic bacteria.  They generally require the presence of a second microbe in co-culture in order to grow.  Few strains are available in captivity, and their growth is restricted to a limited range of organic substrates.  However, they represent an indispensable link in the anaerobic food chains as they perform a set of novel reactions that do not appear to be present in any other bacteria or archaea.

As a first step towards understanding their molecular architecture, we have performed a whole genome analysis of a representative syntroph, S. aciditrophicus.  This delta proteobacterium degrades short chain volatile fatty acids and the aromatic compound benzoate to acetate and hydrogen gas when grown in co-culture.  Genomic analysis reveals that S. aciditrophicus has a 3.1 MB circular genome with 3,169 genes.  We are applying whole genome transcript analysis to identify genes/proteins needed for key biochemical reactions involved in syntrophic growth.  Such findings will facilitate basic and applied studies of this poorly understood class of microorganisms.  This project is in collaboration with Dr. Mike McInerney at the University of Oklahoma.

Click here for S. aciditrophicus  genome sequences.

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Control of aerobic / anaerobic gene expression:

Bose, J.L., Unmi Kim, W. Bartkowski, R.P. Gunsalus, A.M. Overley, N.L. Lyell, K.L. Visick, and E.V. Stabb. 2007. Bioluminescence in Vibrio fischeri is controlled by the redox-responsive regulator ArcA. Molec. Microbiol. 64:538-553.
PMID: 17590235

Salmon, K., S-P. Hung, N.R. Steffen, R. Krupp, P. Baldi, G.W. Hatfield, R.P. Gunsalus. 2005. Global Gene Expression Profiling in Escherichia coli K12: The Effects of Oxygen Availability and ArcA. J. Biol. Chem. 280:15084-96.

Ruby, E.G, Urbanowski, M., Campbell, J.W., Dunn, A., Faini, M.A, Gunsalus, R.P., Lostroh, P., Lupp, C., McCann, J.R., Millikan, D.S., Schaefer, A.L., Stabb, E.V., Stevens, A.M, Visick, K.L., Whistler, C.A. and E.P. Greenberg. 2005. Complete genome sequence of Vibrio fischeri, a mutualistic light-organ symbiont. Proc. Natl. Acad. Sci. U.S. A. 145:3004-3009.

K. Salmon, S-P. Hung, K Mekjian, P. Baldi, G.W. Hatfield, R.P. Gunsalus. 2003. Global Gene Expression Profiling in Escherichia coli K12: the effects of oxygen availability and FNR. J. Biol. Chem. 278:29837-29855.
PMID: 12754220

Bearson, S.M.D., J.A. Albrecht, and R.P. Gunsalus. 2002. Oxygen and nitrate-dependent regulation of dimethylsulfoxide reductase dmsABC operon expression in Escherichia coli: sites for Fnr and NarL protein interactions. BCM Microbiology 2:13.

Govantes, F., A. V. Orjalo, and R.P. Gunsalus. 2000. Interplay between three global regulatory proteins mediates oxygen regulation of the Escherichia coli cytochrome d oxidase (cydAB) operon. Molec. Microbiol. 39:1061-1073.

Govantes, F., J.A. Albrecht, and R.P. Gunsalus. 2000. Oxygen regulation of the Escherichia coli cydAB operon encoding the cytochrome d oxidase: roles of multiple promoters and the Fnr-1 and Fnr-2 binding sites Mol. Microbiol. 37:1-15.

Gunsalus, R.P. 2000. Anaerobic Respiration. 2nd edition, in Encyclopedia of Microbiology. J. Lederberg, ed. Academic Press, San Diego. Volume 1. pp. 180-188.

Cotter, P.A., S. Melville, J. Albrecht, and R.P. Gunsalus. 1997. Aerobic regulation of cytochrome d oxidase (cydAB) operon expression in Escherichia coli: roles of Fnr and ArcA in repression and activation. Molec. Microbiol. 25:605-615.

Shen, J., and R.P. Gunsalus. 1997. Role of multiple ArcA recognition sites in anaerobic regulation of succinate dehydrogenase (sdhCDAB) gene expression in Escherichia coli. Molecular Microbiology 26:223-236.

Kasimoglu, E., S-J. Park, J. Malek, C.P. Tseng, and R.P. Gunsalus. 1996. Transcriptional regulation of the proton-translocating ATP-synthase (atpIBEFHAGDC) operon of Escherichia coli: control by growth rate. J. Bacteriol 178:5563-5576.

Tseng, C-P., J. Albrecht, and R.P. Gunsalus. 1996. Effect of microaerobic cell growth conditions on aerobic (cyoABCDE, cydAB) and anaerobic (narGHJI, frdABCD, dmsABC) respiratory pathway gene expression in Escherichia coli. J. Bacteriol. 178:1094-1098.

Melville, S. and R.P. Gunsalus. 1996. Isolation of an oxygen sensitive FNR protein of Escherichia coli: interaction at activator and repressor sites of FNR controlled genes. Proc. Natl. Acad. Sci. U.S.A. 93:1226-1231.

Chao, G., J. Shen, C.P. Tseng, S.J. Park, and R.P. Gunsalus. 1997. Aerobic regulation of isocitrate dehydrogenase (icd) gene expression in Escherichia coli by the arcA and fnr gene products. J. Bacteriol. 179:4299-4304.

Park, S.J., G. Chao, and R.P. Gunsalus. 1997. Regulation of the sucABCD operon that encodes the a-ketoglutarate dehydrogenase and succinyl-CoA synthetase of Escherichia coli: role of the upstream sdhCDAB promoter, ArcA and Fnr. J. Bacteriol. 179:4138-4142.

Park, S-J., and R.P. Gunsalus. 1995. Oxygen, iron, carbon, and superoxide control of the fumarase fumA and fumC genes of Escherichia coli: role of the arcA, fnr and soxR gene products. J. Bacteriology 177:6255-6262.

Park, S-J., P.A. Cotter, and R.P. Gunsalus. 1995. Regulation of malate dehydrogenase (mdh) gene expression in Escherichia coli in response to oxygen, carbon and heme availability. J. Bacteriology 177:6652-6656.

Park, Soon-Jung, C. P. Tseng, and R.P. Gunsalus. 1995. Regulation of the Escherichia coli succinate dehydrogenase (sdhCDAB) operon in response to anaerobiosis and medium richness: role of the ArcA and Fnr proteins. Molec. Microbiol. 15:473-482.
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Nitrate control:

Maris A.E., M. Kaczor-Grzeskowiak, Z. Ma, M.L. Kopka, R.P. Gunsalus & R.E. Dickerson. 2005. Primary and secondary modes of DNA recognition by the NarL two-component response regulator. Biochemistry 44: 14538-14552.

Wang, H. and R. P. Gunsalus. 2003. Differential regulation of the Escherichia coli formate dehydrogenase fdnGHI and fdhF genes by NarL in response to nitrate, nitrite, and formate. J. Bacteriology 185:5076-5085.
PMID: 12923080

Zhang, J.H., G. Xiao, R.P. Gunsalus, and W.L. Hubble. 2003. Phosphorylation triggers domain separation in the DNA binding response regulator NarL. Biochemistry 42:2552-2559.
PMID: 12614149

Eldridge A.M., H.S. Kang, E. Johnson, R.P. Gunsalus, and F.W. Dahlquist. 2002. Effect of phosphorylation on the interdomain interaction of the response regulator, NarL. Biochemistry 41:15173-15180.

Maris, A.E., M.R. Sawaya, M. Kaczor-Grzeskowiak, M.R. Jarvis, S. Bearson, M.L. Kopka, I. Schroeder, R.P. Gunsalus, and R.E. Dickerson. 2002. Dimerization allows DNA target site recognition by the NarL response regulator. Nature Structural Biology 9:771-778.
PMID: 12352954

Xiao, G, D.L. Cole, R.P. Gunsalus, D. Sigman, and C-H. B. Chen. 2002. Site-specific DNA cleavage of synthetic NarL sites by an engineered Escherichia coli NarL protein -1,10- phenanthroline cleaving agent. Protein Science 11:2427-2436.

Ward, S.M., A. Delgado, R.P. Gunsalus, and M.D. Manson. 2002. A NarX-Tar chimera mediates repellent chemotaxis to nitrate/nitrite. Molec. Microbiol. 44: 709-719

Wang, H., and R. P. Gunsalus. 2000. The nrfA and nirB nitrite reductase operons in Escherichia coli are differentially expressed in response to nitrate in preference to nitrite. J. Bacteriol. 182:5813-5822.

Proctor, L. and R.P. Gunsalus. 2000. Anaerobic respiratory growth of Vibrio harveyi, Vibrio fischeri, and Photobacterium leiognathi with trimethylamine N-oxide, nitrate, and fumarate: Ecological implications. Environmental Microbiology. 2: 399-406.

Wang, H. C-P. Tseng, and R. P. Gunsalus. 1999. The napF and narG nitrate reductase operons in Escherichia coli are differentially expressed in response to sub-micromolar concentrations of nitrate but not nitrite. J. Bacteriol. 181:5303-5308.

Lee, A.I., A. Delgado, and R.P. Gunsalus. 1999. Signal-dependent phosphorylation of the membrane bound NarX two-component sensor-transmitter protein of Escherichia coli: nitrate elicits a superior anion ligand response compared to nitrite. J. Bacteriol. 181:5309-5316.

Baikalov, I., I. Schroeder, M. Kaczor-Grzeskowiak, D. Cascio, R. P. Gunsalus, and R. E. Dickerson. 1998. NarL dimerization? Suggestive evidence from a new crystal form. Biochemistry 37:3665-3676.

Chiang, R., R. Cavicchioli, and R.P. Gunsalus. 1997. Locked-on and locked-off signal transduction mutations in the periplasmic domain of the Escherichia coli NarQ and NarX sensors affect nitrate and nitrite-dependent regulation by NarL and NarP. Molecular Microbiol. 24:1049-1060.

Cavicchioli, R., T. Kolesnikow, R.C. Chiang, and R.P. Gunsalus. 1996. Characterization of the aegA locus of Escherichia coli: control of gene expression in response to anaerobiosis and nitrate. J. Bacteriology 178:6968-6974.

Cavicchioli, R., R. Chaing, L.V. Kalman and R.P. Gunsalus. 1996. Role of the periplasmic domain of the Escherichia coli NarX sensor-transmitter protein in nitrate-dependent signal transduction and gene regulation. Molecular Microbiology 21:901-911.

Baikalov, I., I. Schroeder, M. Kaczor-Grzeskowiak, K. Grzeskowiak, R. P. Gunsalus, and R. E. Dickerson. 1996. The structure of the Escherichia coli response regulator, NarL. Biochemistry 35:11053-11061.

Cavicchioli, R., I. Schröder, M. Constanti, and R.P. Gunsalus. 1995. The Escherichia coli NarQ and NarX regulatory proteins contain two conserved histidines that are required for nitrate dependent signal transduction to NarL. J. Bacteriology 177:2416-2424.
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Metals and Cofactors:

McNicholas, P.M., and R.P. Gunsalus. 2002. The molybdate responsive Escherichia coli ModE transcription factor coordinates periplasmic nitrate reductase (napFDAGHBC) operon expression with nitrate and molybdate availability. J. Bacteriol. 184:3253-3259.

McNicholas, P., M. Mazzotta, S. Rech, and R.P. Gunsalus. 1998. Functional dissection of the molybdate responsive transcription regulator ModE from Escherichia coli. J. Bacteriol. 180:4638-4643.

McNicholas, P.M., R. Chiang, and R.P. Gunsalus. 1998. Regulation of the Escherichia coli dmsABC operon in response to anaerobiosis requires the molybdate responsive regulator, ModE. Molecular Microbiology 27:197-208.

McNicholas, P.M., R. Chiang, and R.P. Gunsalus. 1998. Regulation of the Escherichia coli dmsABC operon in response to anaerobiosis requires the molybdate responsive regulator, ModE. Molecular Microbiology 27:197-208.

Hu, Y. S. Rech, R.P. Gunsalus, and D.C. Rees. 1997. Crystal structure of the molybdate binding protein, ModA. Nature Structural Biology 4:703-707

McNicholas, P.M., S. Rech, and R.P. Gunsalus. 1997. Characterization of ModE DNA binding sites in the control regions of modABCD and moaABCDE of Escherichia coli. Molecular Microbiology 23:515-524.

McNicolas, P., G. Javor, S. Darie, and R.P. Gunsalus. 1997. Expression of the heme biosynthetic pathway genes, hemCD, hemH, hemA, and hemM of Escherichia coli. FEMS Microbiology Letters 146:143-148.

Rech, S., C. Wolin, and R.P. Gunsalus. 1996. Properties of the periplasmic ModA molybdate-binding protein of Escherichia coli. J. Biol. Chem. 271:2557-2562.

McNicholas, P.M., R.C. Chiang, and R.P. Gunsalus. 1996. The Escherichia coli modE gene: effect of modE mutations on molybdate dependent modABCD operon expression. FEMS Microbiology Letters 145:117-123.

Maupin-Furlow, J.A., J.K. Rosentel, J.H. Lee, U. Deppenmeier, R.P. Gunsalus, and K.T. Shanmugam. 1995. Genetic Analysis of modABCE operon (molybdate transport) of Escherichia coli. J. Bacteriology 177:4851-4856.

Rech, S., U. Deppenmeier, and R.P. Gunsalus. 1995. Regulation of the molybdate transport operon, modABCD, of Escherichia coli in response to molybdate availability. J. Bacteriology 177:1023-1029.
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Methanogen projects:

Veit, K., C. Ehlers, A. Ehrenreibch, K. Salmon, R. Hovey, R.P. Gunsalus, U. Deppenmeier, and R.A. Schmitz. 2006. Nitrogen regulation in Methanosarcina mazei strain Gö1: Global transcriptional analysis under different nitrogen availabilities. Molecular Genetics and Genomics 6:41-55.
PMID: 16625354

Li, L, Q. Li, L. Rohlin, UM. Kim, K. Salmon, T. Rejtar, R.P. Gunsalus, B.L. Karger, and J.G. Ferry. 2006. Quantitative proteomic and microarray analysis of the archaeon Methanosarcina acetivorans grown with acetate versus methanol. Journal of Proteome Research 7:759-771.
PMID: 17269732

Ogorzalek Loo, R.R., R. Hayes, Y. Yang, F. Hung, P. Ramachandran, N. Kim, R.P. Gunsalus, and J.A. Loo. 2005. Top-Down, Bottom-Up, and Side-to-Side Proteomics with Virtual 2-D Gels. International Journal of Mass Spectrometry 240:317-325.

Hovey, R., S, Lentes, A. Ehrenreich, K. Salmon, K. Saba, G. Gottschalk, R.P.Gunsalus, and U. Deppenmeier. 2005. DNA microarray analysis of Methanosarcina mazei during growth on methanol and acetate. Molecular Genetics and Genomics 273:225-239.
PMID: 15902489

Rohlin, J.D. Trent, L., K. Salmon, U. Kim, R.P. Gunsalus, and J.C. Liao, 2005, Heat shock response in Archaeoglobus fulgidus. J. Bact. 187:6045-6057.
PMID: 16109946

Deppenmeier, U., A. Johann, T. Hartsch, R. Merkl, R.A. Schmitz, A. Henne, R. Martinez-Arias, A. Wiezer, S. Bäumer, C. Jacobi, H. Brüggemann, T. Lienard, A. Christmann, M. Bömeke, S. Steckel, A. Bhattacharyya, A. Lykidis, R. Overbeek, H-P. Klenk, R.P. Gunsalus, H-J. Fritz, and G. Gottschalk. 2002. The genome of Methanosarcina mazei: Evidence for lateral gene transfer between Bacteria and Archaea. J. Molecular Microbiology and Biotechnology 4:453-461.

Lai, M-C., T.Y. Hong, and R.P. Gunsalus. 2000. Glycine betaine transport in the obligate halophilic Archaean, Methanohalophilus portucalensis. J. Bacteriol. 182: 5020-5024.

Diaz-Perez, S.V., F. Alatriste-Mondragon, R. Hernandez, B. Birren, and R.P. Gunsalus. 1997. Bacterial Artificial Chromosome (BAC) library as a tool for physical mapping of the Archeon Methanosarcina thermophila TM-1. Microbial and Comparative Genomics 2:275-286.

Proctor, L.M., R. Lai and Robert P. Gunsalus. 1997. The methanogenic archaean Methanosarcina thermophila TM-1 possesses a high affinity glycine betaine transporter involved in osmotic adaptation. App. and Environ. Microbiol. 63:2252-2257.

Sowers, K.R., and R.P. Gunsalus. 1995. Halotolerance in the Methanosarcina spp.: role of Ne-acetyl-b-lysine, a-glutamate, glycine betaine, and K+ as compatible solutes for osmotic adaption. App. and Environ. Microbiol. 61:4382-4388.

Gunsalus, R.P. and K. Sowers. 1995. Extraction and detection of compatible intracelluar solutes. in "Protocols for Archaeal Research", pp. 349-368. Cold Spring Harbor Laboratory Press, Cold Spring Harbor, NY.
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Biochemistry of fumarate reductase:

Gunsalus, R.P., G. Cecchini, and I. Schroeder. 2007. Bacterial Respiration in, Methods in General and Molecular Microbiology. ASM Press. ed by A.D. Reddy, et al Chapter 21, pp. 539-557. ASM Press, Washington DC.

Rothery, R.A., A.M. Seime, A.M. C. Spiers, E. Maklashina, I. Schroeder, R. P. Gunsalus, G. Cecchini, and J.H. Weiner. 2005. Defining the Q-site of Escherichia coli fumarate reductase (FrdABCD) by site-directed mutagenesis, fluorescence quench titrations and EPR spectroscopy. FEBS Journal 272:1-14.
PMID: 15654871

Cecchini, G., I. Schröder, R. P. Gunsalus, and E. Maklashina. 2002. Succinate dehydrogenase and fumarate reductase from Escherichia coli. Biochem. Biophys. Acta Rev. in Bioenergetics. 1553:140-157.

Hägerhäll, C., S. Magnitsky, V. Sled, I. Schröder, R. P. Gunsalus, G. Cecchini, and T. Ohnishi. 1999. An Escherichia coli mutant quinol:fumarate reductase contains an EPR detectable semiquinone stabilized at the proximal quinone binding site. Biochemistry 38:26157-26164.

G. Cecchini, H. Sices, I. Schröder, and R.P. Gunsalus. 1995. Aerobic inactivation of fumarate reductase from Escherichia coli by mutation of the [3Fe-4S]-quinone binding domain. J. Bacteriology 177:4587-4592.

Kowal, A.T., M.T. Werth, A. Manodori, G. Cecchini, I Schroeder R.P. Gunsalus, and M.K. Johnson. 1995. Effect of Cysteine to serine mutations on the properties of the [4Fe-4S] center of Escherichia coli fumarate reductase. Biochemistry 34:12284-12293.

Manodori, A., G. Cecchini, I. Schroeder, R.P. Gunsalus, M.T. Werth, and M.K. Johnson. 1992. [3Fe-4S] to [4Fe-4S] cluster conversion in Escherichia coli fumarate reductase by site-directed mutagenesis. Biochemistry 31:2703-2712.

Werth, M.T., H. Sices, G. Cecchini, I. Schroeder, S. Lasage, R.P. Gunsalus, and M.K. Johnson. 1992. Evidence for non-cysteinyl coordination of the [2Fe-2S] cluster in Escherichia coli succinate dehydrogenase. FEBS Letters 299:1-4.

Westenberg, D.J., R. P. Gunsalus, B.A.C. Ackrell, H. Sices, and G. Cecchini. 1993. Escherichia coli fumarate reductase frdC and frdD mutants: identification of amino acid residues involved in catalytic activity with quinones. J. Biol. Chem. 268:815-822.

Ackrell, B.A.C., M.K. Johnson, R.P. Gunsalus and G. Cecchini. 1992. Structure and function of succinate and fumarate reductase. in Chemistry and Biochemistry of Flavoenzymes, Franz Muller, Ed., Vol III. pp. 229-297. CRC Critical Reviews in Biochemistry, CRC Press.

Werth, M.T., G. Cecchini, A. Mandori, B.A.C. Ackrell, I. Schroeder, R.P. Gunsalus, and M.K. Johnson. 1991. Site-directed mutagenesis of active site cysteine residues in Escherichia coli fumarate reductase. J. Inorganic Biochem. 43:270.

Schroeder, I., R.P. Gunsalus, B.A.C. Ackrell, B. Cochran, and G. Cecchini. 1991. Identification of active site residues of Escherichia coli fumarate reductase by site-directed mutagenesis. J. Biol. Chem. 266:13572-13579.

Westenberg, D.J., R.P. Gunsalus, B.A.C. Ackrell, and G. Cecchini. 1990. Electron Transfer from Menaquinol to Fumarate: Fumarate Reductase Anchor Polypeptide Mutants of Escherichia coli. J. Biol. Chem. 265:19560-19567.

Werth, M.T., G. Cecchini, A. Manodori, B.A.C. Ackrell, I. Schroeder, R.P. Gunsalus, and M.K. Johnson. 1990. Site-directed mutagenesis of conserved cysteine residues in Escherichia coli fumarate reductase: Modification of the spectroscopic and electrochemical properties of the [2Fe-2S] cluster. Proc. Natl. Acad. Sci. USA. 87:8965-8969.
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Syntrophic microbiology:

McInerney, M., L. Rohlin, H. Moutakki, U-M. Kim, R. Krupp, L. Rio-Hernandez. A. Bhattacharyya, J. Campbell, and R.P. Gunsalus. 2007. Genome of the syntrophic bacterium Syntrophus aciditrophicus: life at the thermodynamic limit of microbial growth. Proc. Nat.Acad. Sci. U.S. A.104:7600-7605.
PMID: 17442750

McInerney, M.J., C.G. Struchtemeyer, J. Sieber, H. Mouttaki, A.J.M. Stams, B. Schink, L. Rohlin, and R.P. Gunsalus. 2007. Physiology, ecology, phylogeny, and genomics of microorganisms capable of syntrophic metabolism. Anal. N.Y. Acad. Sci. (in press).

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Click Images for Enlarged Versions

Stereo superposition of the three NarLC-DNA complexes

Molybdate sensing in the cytoplasm by ModE

The N and C terminal domains of NarL

NarL contacts in major groove of DNA

NarL N-terminal domain

NarL crystals I222 symmetry

NarX signal transduction originates in the cell periplasmic space.

The Fnr, ArcAB, NarXLQ regulatory scheme for E. coli respiratory pathway genes.

Differential expression of the napF and narG nitrate redutcase operons in E. coli

Nitrate-dependent NarX phosphorylation occurs at two orders of magnitude lower concentration than for nitrite

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
(310) 206-5231  fax

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