title: [FeFe]- and [NiFe]-hydrogenase diversity, mechanism, and maturation.
abstract: The [FeFe]- and [NiFe]-hydrogenases catalyze the formal interconversion between hydrogen and protons and electrons, possess characteristic non-protein ligands at their catalytic sites and thus share common mechanistic features. Despite the similarities between these two types of hydrogenases, they clearly have distinct evolutionary origins and likely emerged from different selective pressures. [FeFe]-hydrogenases are widely distributed in fermentative anaerobic microorganisms and likely evolved under selective pressure to couple hydrogen production to the recycling of electron carriers that accumulate during anaerobic metabolism. In contrast, many [NiFe]-hydrogenases catalyze hydrogen oxidation as part of energy metabolism and were likely key enzymes in early life and arguably represent the predecessors of modern respiratory metabolism. Although the reversible combination of protons and electrons to generate hydrogen gas is the simplest of chemical reactions, the [FeFe]- and [NiFe]-hydrogenases have distinct mechanisms and differ in the fundamental chemistry associated with proton transfer and control of electron flow that also help to define catalytic bias. A unifying feature of these enzymes is that hydrogen activation itself has been restricted to one solution involving diatomic ligands (carbon monoxide and cyanide) bound to an Fe ion. On the other hand, and quite remarkably, the biosynthetic mechanisms to produce these ligands are exclusive to each type of enzyme. Furthermore, these mechanisms represent two independent solutions to the formation of complex bioinorganic active sites for catalyzing the simplest of chemical reactions, reversible hydrogen oxidation. As such, the [FeFe]- and [NiFe]-hydrogenases are arguably the most profound case of convergent evolution. This article is part of a Special Issue entitled: Fe/S proteins: Analysis, structure, function, biogenesis and diseases.
authors.affiliation: Department of Chemistry and Biochemistry, Montana State University, Bozeman, MT 59717, USA. Electronic address: john.peters@chemistry.montana.edu.
authors.forename: John W
authors.initials: JW
authors.lastname: Peters
authors.affiliation: Department of Biochemistry and Molecular Biology, University of Georgia, Athens, GA 30602, USA.
authors.forename: Gerrit J
authors.initials: GJ
authors.lastname: Schut
authors.affiliation: Department of Microbiology and Immunology, Montana State University, Bozeman, MT 59717, USA.
authors.forename: Eric S
authors.initials: ES
authors.lastname: Boyd
authors.affiliation: Biosciences Center, National Renewable Energy Laboratory, Golden, CO 80401, USA.
authors.forename: David W
authors.initials: DW
authors.lastname: Mulder
authors.affiliation: Department of Chemistry and Biochemistry, Montana State University, Bozeman, MT 59717, USA.
authors.forename: Eric M
authors.initials: EM
authors.lastname: Shepard
authors.affiliation: Department of Chemistry and Biochemistry, Montana State University, Bozeman, MT 59717, USA.
authors.forename: Joan B
authors.initials: JB
authors.lastname: Broderick
authors.affiliation: Biosciences Center, National Renewable Energy Laboratory, Golden, CO 80401, USA.
authors.forename: Paul W
authors.initials: PW
authors.lastname: King
authors.affiliation: Department of Biochemistry and Molecular Biology, University of Georgia, Athens, GA 30602, USA.
authors.forename: Michael W W
authors.initials: MW
authors.lastname: Adams
mesh_terms: D001105:Archaea / Q000145:classification / Q000201:enzymology / Q000235:genetics; D019843:Archaeal Proteins / Q000235:genetics / Q000378:metabolism*; D001419:Bacteria / Q000145:classification / Q000201:enzymology / Q000235:genetics; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism*; D014644:Genetic Variation; D006859:Hydrogen / Q000378:metabolism*; D006864:Hydrogenase / Q000235:genetics / Q000378:metabolism*; D007506:Iron-Sulfur Proteins / Q000235:genetics / Q000378:metabolism*; D010084:Oxidation-Reduction; D010802:Phylogeny
chemical_list: D019843:Archaeal Proteins; D001426:Bacterial Proteins; D007506:Iron-Sulfur Proteins; D006859:Hydrogen; C118830:iron hydrogenase; C043296:nickel-iron hydrogenase; D006864:Hydrogenase
keywords: Bifurcation; Carbon monoxide; Cyanide; Hydrogen oxidation; Iron-sulfur; Proton reduction