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Adenylylsulfate reductases from archaea and bacteria are 1:1 αβ‐heterodimeric iron–sulfur flavoenzymes – high similarity of molecular properties emphasizes their central role in sulfur metabolism
Author(s) -
Fritz Günter,
Büchert Thomas,
Huber Harald,
Stetter Karl O.,
Kroneck Peter M.H.
Publication year - 2000
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/s0014-5793(00)01500-3
Subject(s) - archaea , cofactor , sulfur metabolism , bacteria , sulfite reductase , enzyme , sulfur , protein subunit , biochemistry , ferredoxin , chemistry , reductase , sulfate reducing bacteria , biology , stereochemistry , gene , genetics , organic chemistry
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 αβ‐heterodimer of molecular mass ≈95 kDa, and two subunits (α≈75, β≈20 kDa). The specific activity was 11–14 μmol (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 α‐subunit, and two [4Fe–4S] centers located in close proximity on the β‐subunit.