Contact Information

Chemistry and Biochemistry Building
P.O. Box 173400
Bozeman, MT 59717

Phone: 406-994-4801


Research Group Website



  • B.S. 1989 Microbiology, University of Oklahoma, Norman, OK
  • Ph.D. 1995 Biochemistry, Virginia Tech, Blacksburg, Va.
  • Postdoc: 1995-1997 California Institute of Technology


Awards and Professional Activities

  • MSU 2010, Ross Provost’s Award for Excellence in Research and Teaching
  • Wiley Award for Meritorious Research, 2006
  • Chair, 2006 Gordon Conference on Iron-Sulfur Enzymes
  • Camille Dreyfus Teacher/Scholar Award, 2001
  • Atorvastatin Research Award, 2000
  • NIH Postdoctoral Fellow, Chemistry, California Institute of Technology, 1995-1996

Nitrogenase and Nitrogen Reduction

The broad, long term goal of the project is to gain structural and mechanistic insights into the role of MgATP in nitrogenase catalysis. Nitrogenase is a complex metal-containing enzyme that catalyzes the conversion of nitrogen gas to ammonia. During nitrogenase catalysis, the iron protein and molybdenum-iron protein associate and dissociate in a manner resulting in the hydrolysis of two molecules of MgATP and the transfer of at least one electron to the MoFe protein. Multiple cycles of iron protein association and dissociation, MgATP hydrolysis, and electron transfer are required for the complete reduction of a single molecule of nitrogen to ammonia. There are a number of aspects of nitrogenase structure/function that are interesting areas of fundamental research. Nitrogenase can be considered an ideal model system for the study of the complex metal cluster mediated catalysis, electron transfer, complex metal cluster assembly, protein-protein interactions, and nucleotide dependent signal transduction. In addition, the involvement of MgATP in nitrogenase catalysis is similar to the role of nucleotides in a large class of nucleotide binding proteins that couple nucleotide binding and hydrolysis to protein conformational changes transduced within a macromolecular assembly. Members of the class include G proteins, Ras p21, RecA, elongation factor Tu, myosin, and transducin, making the role of MgATP binding and hydrolysis one of the most fascinating aspects of nitrogenase research. We have recently been able to determine the structure of a single deletion mutant of the nitrogenase Fe protein that provides a structural mimic of the MgATP bound state. The structural insights described in the preliminary results section of the proposal provide the firmest foundation described to date for generating hypotheses concerning MgATP dependent conformational change in the Fe protein and the initial component protein interactions that trigger MgATP hydrolysis. The proposed studies apply a combined approach involving structure determination by x-ray diffraction methods and site-specific amino acid substitution experiments to gain insights into nucleotide dependent conformational change, macromolecular complex formation, and the specific protein-protein interactions occurring upon complex formation that initiate MgATP hydrolysis in nitrogenase.



Novel Enzymeatic Carboxylation

Epoxides and ketones are widely used in industry and have been shown to have potential mutagenic, carcinogenic, and toxic effects. Therefore, there is considerable interest in microbial based bioconversions of these compounds into less environmentally detrimental compounds. Epoxides are utilized in a variety of industrial processes as intermediates in organic synthesis. Due to the strained three-membered ring structure of these compounds, epoxides react readily with a number of nucleophiles {Swaving, 1998 #1315}. Optically pure epoxides are intermediates in the synthesis of a number of bioactive compounds including leukotrienes, pheromones, antibiotics, and an HIV protease inhibitor. Due to the reactive nature of these compounds and their ability to react with cellular components including DNA and proteins, they are of considerable concern as potential human health hazards. The ability of epoxides to form covalent adducts to DNA can result in mutagenic and carcinogenic effects. Acetone is a toxic molecule that is synthesized industrially and formed biologically during bacterial fermentation and mammalian starvation. A number of bacteria are able to grow with acetone as a source of carbon and energy. In addition, acetone is formed as an intermediate in the metabolism of propane and isopropanol by some bacteria. Bacterial pathways of acetone metabolism and the biochemical properties of acetone-metabolizing enzymes are poorly understood. The widespread use of epoxides and ketones has resulted in an increased interest in the mechanisms by which various microorganisms transform these compounds into less environmentally detrimental compounds. From a basic science standpoint the bioconversions we propose to study represent novel microbial based CO2 fixation / carboxylation mechanisms that have only recently been identified. The results obtained in the study will reveal new insights into these novel carboxylation reactions and will provide the basis for the comparison of the mechanism of these interesting enzymes to other more well characterized CO2 fixing and carboxylating enzymes.



Hydrogenase and Reversible Hydrogen Oxidation

The reversible conversion of molecular hydrogen to protons and electrons is a central reaction in the global biological energy cycle. Hydrogenase enzymes catalyze a large percentage of this reaction, and thus a more detailed understanding of these enzymes is of wide interest in biotechnology, biochemistry, and energy sciences. These enzymes are present in various microorganisms and function either in the utilization of Hydrogen as a growth substrate (Hydrogen uptake) or in certain anaerobic bacteria to dispose of excess electrons by combining them with protons to form Hydrogen. The X-ray crystal structure of the iron-only hydrogenase from the anaerobic soil microorganism Clostridium pasteurianum (CpI) was determined to 1.8 angstrom resolution in the group. CpI is a highly complex protein containing twenty iron atoms arranged into five individual metal cluster assemblies. The active site cluster or "H cluster" is structurally unprecedented among previously characterized biological iron-sulfur clusters. Our ongoing hydrogenase research involves probing the mechanism of hydrogenases by biochemical, structural, and physical methods. We are collaborating with Prof. Joan Broderick of the department on the mechanism of the H cluster. In addition, we are collaborating with investigators throughout the world, probing avenues to produce hydrogen efficiently as renewable energy. This work includes a collaboration here at MSU with Trevor Douglas of the department on the design, synthesis, and characterization of hydrogen producing biomimetic materials.



Recent Publications

Broderick JB, Byer AS, Duschene KS, Duffus BR, Betz JN, Shepard EM, Peters JW. H-Cluster assembly during maturation of the [FeFe]-hydrogenase. J Biol Inorg Chem. 2014 Jun 28. [Epub ahead of print]

Shepard EM, Mus F, Betz JN, Byer AS, Duffus BR, Peters JW, Broderick JB. [FeFe]-Hydrogenase Maturation. Biochemistry. 2014 Jul 1;53(25):4090-104

D'Adamo S, Jinkerson RE, Boyd ES, Brown SL, Baxter BK, Peters JW, Posewitz MC. Evolutionary and biotechnological implications of robust hydrogenase activity in halophilic strains of tetraselmis. PLoS One. 2014 Jan 21;9(1).

Hamilton TL, Koonce E, Howells A, Havig JR, Jewell T, de la Torre JR, Peters JW, Boyd ES. Competition for ammonia influences the structure of chemotrophic communities in geothermal springs. Appl Environ Microbiol. 2014 Jan;80(2):653-61.

Heinemann J, Hamerly T, Maaty WS, Movahed N, Steffens JD, Reeves BD, Hilmer JK, Therien J, Grieco PA, Peters JW, Bothner B. Expanding the paradigm of thiol redox in the thermophilic root of life. 2014 Jan;1840(1):80-5

Boyd ES, Schut GJ, Adams MWW, Peters JW. Hydrogen Metabolism and the Evolution of Biological Respiration. Feature Article in ASM Microbe 9;361-67 (2014)

Schut GJ, Boyd ES, Peters JW, Adams MW. The modular respiratory complexes involved in hydrogen and sulfur metabolism by heterotrophic hyperthermophilic archaea and their evolutionary implications. FEMS Microbiol Rev. 37:182-203 (2013)

Boyd ES, Peters JW. New insights into the evolutionary history of biological nitrogen fixation. Front Microbiol. 2013 Aug 5;4:201. doi: 10.3389/fmicb.2013.00201.
[Epub ahead of print]

Hamilton TL, Peters JW, Skidmore ML, Boyd ES.”Molecular evidence for an active endogenous microbiome beneath glacial ice”. 2013, ISME J. 7(7):1402-12

Mulder DW, Ratzloff MW, Shepard EM, Byer AS, Noone SM, Peters JW, Broderick JB, King PW. “EPR and FTIR Analysis on the Mechanism of H2 Activation by [FeFe]-Hydrogenase HydA1 from Chlamydomonas reinhardtii”. 2013, JACS. 135(18):6921-9

Mitra D, George SJ, Guo Y, Kamali S, Keable S, Peters JW, Pelmenschikov V, Case DA, Cramer SP. "Characterization of [4Fe-4S] Cluster Vibrations and Structure in Nitrogenase Fe Protein at Three Oxidation Levels via Combined NRVS, EXAFS, and DFT Analyses". 2013, J Am Chem Soc. 135(7):2530-43

Meuser JE, Baxter BK, Spear JR, Peters JW, Posewitz MC, Boyd ES. "Contrasting Patterns of Community Assembly in the Stratified Water Column of Great Salt Lake, Utah". 2013, Microb Ecol. 66(2):268

Hamilton TL, Ludwig M, Dixon R, Boyd ES, Dos Santos PC, Setubal JC, Bryant DA, Dean DR, Peters JW. Transcriptional profiling of nitrogen fixation in Azotobacter vinelandii. J Bacteriol. 193:4477-86 (2011) – highlighted in ASM Microbe

Boyd ES, Anbar AD, Miller S, Hamilton TL, Lavin M, and Peters JW “A late methanogen origin for molybdenum-dependent nitrogenase” Geobiology 9:221-232 (2011) – highlighted in Science as Editor’s Choice

Mulder, DW; Boyd, ES; Sarma, R; Lange, RK; Endrizzi, JA; Broderick, JB; Peters, JW. Stepwise [FeFe]-hydrogenase H-cluster assembly revealed in the structure of HydA(DeltaEFG). Nature 465: 248-251 (2010) – highlighted in Angew Chem Int Ed Engl.

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