Structural, biochemical and genetic characterization of dissimilatory ATP sulfurylase from Allochromatium vinosum

• Published in: PloS one Vol. 8; no. 9; p. e74707
• Main Authors: Parey, Kristian, Demmer, Ulrike, Warkentin, Eberhard, Wynen, Astrid, Ermler, Ulrich, Dahl, Christiane
• Format: Journal Article
• Language: English
• Published: United States Public Library of Science 20.09.2013; Public Library of Science (PLoS)
• Subjects: Adenosine; Adenosine Phosphosulfate - metabolism; Adenosine Triphosphate - metabolism; Amino Acid Sequence; ATP; ATP sulfurylase; Automation; Bacteria; Bacterial Proteins - genetics; Bacterial Proteins - metabolism; Chromatiaceae - enzymology; Crystal structure; Diphosphates - metabolism; E coli; Enzymes; Escherichia coli - enzymology; Escherichia coli - genetics; Fungi; Genes; Genetic aspects; Genetic engineering; Genomes; Kinases; Molecular Sequence Data; Mutagenesis; Oxidation; Phosphates; Protein Conformation; Recombinant proteins; Recombinant Proteins - genetics; Recombinant Proteins - metabolism; Reductase; Sat gene; Sequence Homology, Amino Acid; Structural analysis; Substrates; Sulfate; Sulfate Adenylyltransferase - chemistry; Sulfate Adenylyltransferase - genetics; Sulfate Adenylyltransferase - metabolism; Sulfates; Sulfates - metabolism; Sulfite; Sulfites; Sulfur; Sulfur compounds; Sulfur cycle; Germany
• ISSN: 1932-6203; 1932-6203
• DOI: 10.1371/journal.pone.0074707

ATP sulfurylase (ATPS) catalyzes a key reaction in the global sulfur cycle by reversibly converting inorganic sulfate (SO4 (2-)) with ATP to adenosine 5'-phosphosulfate (APS) and pyrophosphate (PPi). In this work we report on the sat encoded dissimilatory ATP sulfurylase from the sulfur-oxidizing purple sulfur bacterium Allochromatium vinosum. In this organism, the sat gene is located in one operon and co-transcribed with the aprMBA genes for membrane-bound APS reductase. Like APS reductase, Sat is dispensible for growth on reduced sulfur compounds due to the presence of an alternate, so far unidentified sulfite-oxidizing pathway in A. vinosum. Sulfate assimilation also proceeds independently of Sat by a separate pathway involving a cysDN-encoded assimilatory ATP sulfurylase. We produced the purple bacterial sat-encoded ATP sulfurylase as a recombinant protein in E. coli, determined crucial kinetic parameters and obtained a crystal structure in an open state with a ligand-free active site. By comparison with several known structures of the ATPS-APS complex in the closed state a scenario about substrate-induced conformational changes was worked out. Despite different kinetic properties ATPS involved in sulfur-oxidizing and sulfate-reducing processes are not distinguishable on a structural level presumably due to the interference between functional and evolutionary processes.