title: Archaeal complex II: 'classical' and 'non-classical' succinate:quinone reductases with unusual features.
abstract: Reversible succinate dehydrogenase (SDH) activities have been ubiquitously detected in organisms from the three domains of life. They represent constituents either of respiratory complexes II in aerobes, or of fumarate dehydrogenase complexes in anaerobes. The present review gives a survey on archaeal succinate:quinone oxidoreductases (SQRs) analyzed so far. Though some of these could be studied in detail enzymologically and spectroscopically, the existence of others has been deduced only from published genome sequences. Interestingly, two groups of enzyme complexes can be distinguished in Archaea. One group resembles the properties of SDHs known from bacteria and mitochondria. The other represents a novel class with an unusual iron-sulfur cluster in subunit B and atypical sequence motifs in subunit C which may influence electron transport mechanisms and pathways. This novel class of SQRs is discussed in comparison to the so-called 'classical' complexes. A phylogenetic analysis is presented suggesting a co-evolution of the flavoprotein-binding subunit A and subunit B containing the three iron-sulfur clusters.
authors.affiliation: Institute of Biochemistry, Medical University of Lübeck, D-23538, Lübeck, Germany. schaefer@biochem.mu-luebeck.de
authors.forename: Günter
authors.initials: G
authors.lastname: Schäfer
authors.forename: Stefan
authors.initials: S
authors.lastname: Anemüller
authors.forename: Ralf
authors.initials: R
authors.lastname: Moll
mesh_terms: D000595:Amino Acid Sequence; D001105:Archaea / Q000145:classification / Q000201:enzymology*; D042963:Electron Transport Complex II; D019143:Evolution, Molecular; D005650:Fumarates / Q000378:metabolism; D007506:Iron-Sulfur Proteins / Q000235:genetics; D008969:Molecular Sequence Data; D009097:Multienzyme Complexes / Q000737:chemistry / Q000378:metabolism*; D009876:Operon; D010084:Oxidation-Reduction; D010088:Oxidoreductases / Q000737:chemistry / Q000378:metabolism*; D010802:Phylogeny; D016415:Sequence Alignment; D013385:Succinate Dehydrogenase / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D019802:Succinic Acid / Q000378:metabolism
chemical_list: D005650:Fumarates; D007506:Iron-Sulfur Proteins; D009097:Multienzyme Complexes; C032005:fumaric acid; D019802:Succinic Acid; D010088:Oxidoreductases; D042963:Electron Transport Complex II; D013385:Succinate Dehydrogenase