Classification and phylogeny of hydrogenases.

摘要: Hydrogenases (H2ases) catalyze the reversible oxidation of molecular hydrogen and play a central role in microbial energy metabolism. Most these enzymes are found Archaea Bacteria, but few present Eucarya as well. They can be distributed into three classes: [Fe]-H2ases, [NiFe]-H2ases, metal-free H2ases. The vast majority known H2ases belong to first two classes, over 100 have been characterized genetically and/or biochemically. Compelling evidence from sequences structures indicates that [NiFe]- [Fe]-H2ases phylogenetically distinct classes proteins. catalytic core [NiFe]-H2ases is heterodimeric protein, although additional subunits many enzymes. Functional defined, they consistent with categories defined by sequence similarity subunits. ca. 350-residue domain accommodates active site (H-cluster). A monomeric barely larger than H-cluster domain. Many others well, possess domains contain redox centers, mostly iron–sulfur. Some oligomeric. modular structure strikingly illustrated recently unveiled structures. It also remarkable most accessory counterparts other complexes, particular NADH-ubiquinone oxidoreductase (Complex I) respiratory chains. Microbial genome bringing forth significant body H2ase data contribute understanding distribution evolution. Altogether, available suggest restricted Bacteria Eucarya, while one possible exception, seem only Bacteria. processing maturation involve products several genes which identified currently being case [NiFe]-H2ases. In contrast, near nothing regarding [Fe]-H2ases. Inspection suggests [NiFe]-H2ase proteins no similar genomes organisms possessing only. This observation, if confirmed, would phylogenetic distinctiveness Sequence alignments implemented construct trees were consistent, main, derived data. On basis comparisons performed discussed here, proposals made simplify rationalize nomenclature H2ase-encoding genes.