title: Adenylylsulfate reductases from archaea and bacteria are 1:1 alphabeta-heterodimeric iron-sulfur flavoenzymes--high similarity of molecular properties emphasizes their central role in sulfur metabolism.
abstract: Highly active adenylylsulfate (APS) reductase was isolated under N(2)/H(2) from sulfate-reducing and sulfide-oxidizing bacteria and archaea. It was a 1:1 alphabeta-heterodimer of molecular mass approximately 95 kDa, and two subunits (alpha approximately 75, beta approximately 20 kDa). The specific activity was 11-14 micromol (min mg)(-1); cofactor analysis revealed 0.96+/-0.05 FAD, 7.5+/-0.1 Fe and 7.9+/-0.25 S(2-). The photochemically reduced enzyme had a multiline EPR spectrum resulting from two interacting [4Fe-4S] centers. The properties of the different APS reductases were remarkably similar, although the enzyme is involved in different metabolic pathways and was isolated from phylogenetically far separated organisms. A structural model is proposed, with FAD bound to the alpha-subunit, and two [4Fe-4S] centers located in close proximity on the beta-subunit.
authors.affiliation: Fakultät für Biologie, Universität Konstanz, D-78457, Konstanz, Germany. gfritz@bioc.unizh.ch
authors.forename: G
authors.initials: G
authors.lastname: Fritz
authors.forename: T
authors.initials: T
authors.lastname: Büchert
authors.forename: H
authors.initials: H
authors.lastname: Huber
authors.forename: K O
authors.initials: KO
authors.lastname: Stetter
authors.forename: P M
authors.initials: PM
authors.lastname: Kroneck
mesh_terms: D000249:Adenosine Monophosphate / Q000378:metabolism; D020816:Amino Acid Motifs; D019611:Archaeoglobus fulgidus / Q000201:enzymology* / Q000235:genetics / Q000378:metabolism; D001665:Binding Sites; D003545:Cysteine / Q000235:genetics / Q000378:metabolism; D003901:Desulfovibrio / Q000201:enzymology* / Q000235:genetics / Q000378:metabolism; D016969:Desulfovibrio vulgaris / Q000201:enzymology / Q000235:genetics / Q000378:metabolism; D019281:Dimerization; D004578:Electron Spin Resonance Spectroscopy; D005182:Flavin-Adenine Dinucleotide / Q000032:analysis / Q000378:metabolism; D005798:Genes, Bacterial / Q000235:genetics; D007501:Iron / Q000032:analysis / Q000378:metabolism; D007506:Iron-Sulfur Proteins / Q000737:chemistry / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D008958:Models, Molecular; D008970:Molecular Weight; D009876:Operon / Q000235:genetics; D010084:Oxidation-Reduction; D010088:Oxidoreductases / Q000737:chemistry / Q000235:genetics / Q000302:isolation & purification* / Q000378:metabolism*; D050862:Oxidoreductases Acting on Sulfur Group Donors; D017386:Sequence Homology, Amino Acid; D013053:Spectrophotometry; D013455:Sulfur / Q000032:analysis / Q000378:metabolism*; D013457:Sulfur Compounds / Q000378:metabolism
chemical_list: D007506:Iron-Sulfur Proteins; D013457:Sulfur Compounds; D005182:Flavin-Adenine Dinucleotide; D000249:Adenosine Monophosphate; D013455:Sulfur; D007501:Iron; D010088:Oxidoreductases; D050862:Oxidoreductases Acting on Sulfur Group Donors; C019618:adenylylsulfate reductase; D003545:Cysteine