title: The 'strict' anaerobe Desulfovibrio gigas contains a membrane-bound oxygen-reducing respiratory chain.
abstract: Sulfate-reducing bacteria are considered as strict anaerobic microorganisms, in spite of the fact that some strains have been shown to tolerate the transient presence of dioxygen. This report shows that membranes from Desulfovibrio gigas grown in fumarate/sulfate contain a respiratory chain fully competent to reduce dioxygen to water. In particular, a membrane-bound terminal oxygen reductase, of the cytochrome bd family, was isolated, characterized, and shown to completely reduce oxygen to water. This oxidase has two subunits with apparent molecular masses of 40 and 29 kDa. Using NADH or succinate as electron donors, the oxygen respiratory rates of D. gigas membranes are comparable to those of aerobic organisms (3.2 and 29 nmol O(2) min(-1) mg protein(-1), respectively). This 'strict anaerobic' bacterium contains all the necessary enzymatic complexes to live aerobically, showing that the relationships between oxygen and anaerobes are much more complex than originally thought.
authors.affiliation: Instituto de Tecnologia Química e Biológica, Universidade Nova de Lisboa, Oeiras, Portugal.
authors.forename: R S
authors.initials: RS
authors.lastname: Lemos
authors.forename: C M
authors.initials: CM
authors.lastname: Gomes
authors.forename: M
authors.initials: M
authors.lastname: Santana
authors.forename: J
authors.initials: J
authors.lastname: LeGall
authors.forename: A V
authors.initials: AV
authors.lastname: Xavier
authors.forename: M
authors.initials: M
authors.lastname: Teixeira
mesh_terms: D000693:Anaerobiosis; D016227:Benzoquinones / Q000378:metabolism; D002462:Cell Membrane / Q000737:chemistry / Q000378:metabolism; D003573:Cytochrome b Group; D003580:Cytochromes / Q000037:antagonists & inhibitors / Q000737:chemistry / Q000378:metabolism*; D003901:Desulfovibrio / Q000378:metabolism*; D004579:Electron Transport / Q000502:physiology*; D045222:Electron Transport Chain Complex Proteins; D004791:Enzyme Inhibitors / Q000494:pharmacology; D029968:Escherichia coli Proteins; D005650:Fumarates / Q000378:metabolism; D009243:NAD / Q000378:metabolism; D010084:Oxidation-Reduction; D010088:Oxidoreductases / Q000037:antagonists & inhibitors / Q000737:chemistry / Q000378:metabolism*; D010100:Oxygen / Q000378:metabolism*; D010101:Oxygen Consumption / Q000502:physiology; D011809:Quinones / Q000378:metabolism; D019802:Succinic Acid / Q000378:metabolism; D013431:Sulfates / Q000378:metabolism
chemical_list: D016227:Benzoquinones; D003573:Cytochrome b Group; D003580:Cytochromes; D045222:Electron Transport Chain Complex Proteins; D004791:Enzyme Inhibitors; D029968:Escherichia coli Proteins; D005650:Fumarates; D011809:Quinones; D013431:Sulfates; D009243:NAD; C032005:fumaric acid; D019802:Succinic Acid; D010088:Oxidoreductases; C040077:cytochrome bd terminal oxidase complex, E coli; D010100:Oxygen; C034257:duroquinone