Eric Boyd
Montana State University

Research Activities

The emergence of metalloenzymes capable of activating substrates such as CO, N2, and H2, were significant advancements in biochemical reactivity and in the evolution of complex life. Examples of such enzymes include [FeFe]- and [NiFe]-hydrogenase that function in H2 metabolism and Mo-, V-, and Fe-nitrogenases that function in N2 reduction. Many of these metalloenzymes have closely related paralogs that catalyze distinctly different chemistries, an example being nitrogenase and its closely related paralog protochlorophyllide reductase that functions in the biosynthesis of bacteriochlorophyll (photosynthesis). While the amino acid composition of these closely related paralogs are often similar, their biochemical reactivity and substrate specificity are often quite different. This phenomenon is a direct consequence of the composition and molecular structure of the active site metallocluster, which requires a number of accessory proteins to synthesize. By specifically focusing on the origin and subsequent evolution of these metallocluster biosynthesis proteins in relation to paralogous proteins that have left clear evidence in the geological record (photosynthesis and the rise of O2), we have been able to obtain significant insight into the origin and evolution of these functional processes, and to place these events in evolutionary time. In parallel to our evolutionary studies, we are examining the distribution and diversity of genes that encode for these proteins in environments with physical and chemical properties that are thought to be analogous to early Earth. Such environments include the geothermal springs in Yellowstone National Park, Wyoming and various saline environments in Utah and Northern Mexico. Using a number of computational approaches, we have been able to deduce the primary environmental parameters that constrain the distribution of these functional processes and which underpin their diversity. Such information is central to constraining the parameter space of environment types that are likely to have facilitated the emergence of these metal-based biocatalysts.

Selected Publications

Meuser, J.E., E.S Boyd, G. Ananyev, D. Karns, N.U.M. Murthy, R. Radakovits, , M.L. Ghirardi, J.W. Peters, and M.C. Posewitz. 2011. Evolutionary significance of an algal gene encoding an [FeFe]-hydrogenase with F-domain homology and hydrogenase activity in Chlorella variabilis NC64A. In press.

Hamilton, T.L., R.K. Lange, E.S. Boyd* and J.W. Peters. 2011. Biological nitrogen fixation in acidic high temperature geothermal springs in Yellowstone National Park, Wyoming. Environ. Microbiol. doi: 10.1111/j.1462-2920.2011.02475.x.

Hamilton, T.L., E.S. Boyd, and J.W. Peters. 2011. Environmental constraints underpin the distribution
and phylogenetic diversity of nifH in the Yellowstone geothermal complex. Microbiol. Ecol. doi: 10.1007/s00248-011-9824-9.

Boyd, E.S., A.D. Anbar, S.R. Miller, T.L. Hamilton, M. Lavin, and J.W. Peters. 2011. A late methanogen origin for the molybdenum-dependent nitrogenase. Geobiology. 9(3):221-232.

Shepard, E.M., E.S. Boyd, J.B. Broderick, and J.W. Peters. 2011. Biosynthesis of complex iron-sulfur enzymes. Curr Opin Chem Biol. 15(2):319-27.

Boyd, E.S., T.L. Hamilton, J.R. Spear, M. Lavin, and J.W. Peters. 2010. [FeFe]-hydrogenase in Yellowstone National Park: evidence of dispersal limitation and phylogenetic niche conservatism. ISME J. 4:1485–1495.

Barkay, T., K. Kritee, E.S. Boyd, and G.G. Geesey. 2010. A thermophilic bacterial origin and subsequent constraints by redox, light, and salinity on the evolution of the microbial mercuric reductase. Environ. Microbiol. 12(11):2904-2917.

Mulder, D.M., E.S. Boyd, R. Sarma, J.A. Endrizzi, R. Lange, J.B. Broderick and J.W. Peters. 2010. Structure of HydA?EFG, a key intermediate in [FeFe]-hydrogenase H-cluster biosynthesis. Nature. 465: 248-252.

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Current NAI Teams