Structural, biochemical and genetic characterization of dissimilatory ATP sulfurylase from Allochromatium vinosum.
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.
Max-Planck-Institut für Biophysik, Frankfurt, Germany ; Institut für Biophysik und Physikalische Biochemie, Universität Regensburg, Regensburg, Germany.
Kristian
K
Parey
Ulrike
U
Demmer
Eberhard
E
Warkentin
Astrid
A
Wynen
Ulrich
U
Ermler
Christiane
C
Dahl
D000250:Adenosine Phosphosulfate / Q000378:metabolism; D000255:Adenosine Triphosphate / Q000378:metabolism*; D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism; D002841:Chromatiaceae / Q000201:enzymology*; D011756:Diphosphates / Q000378:metabolism; D004926:Escherichia coli / Q000201:enzymology* / Q000235:genetics; D008969:Molecular Sequence Data; D011487:Protein Conformation; D011994:Recombinant Proteins / Q000235:genetics / Q000378:metabolism; D017386:Sequence Homology, Amino Acid; D013430:Sulfate Adenylyltransferase / Q000737:chemistry* / Q000235:genetics* / Q000378:metabolism; D013431:Sulfates / Q000378:metabolism*
D001426:Bacterial Proteins; D011756:Diphosphates; D011994:Recombinant Proteins; D013431:Sulfates; D000250:Adenosine Phosphosulfate; C107241:diphosphoric acid; D000255:Adenosine Triphosphate; D013430:Sulfate Adenylyltransferase