32] Dissimilatory ATP sulfurylase from Archaeoglobus fulgidus

Abstract

Publisher Summary The hyperthermophilic sulfate-reducing archaeon Archaeoglobus fulgidus belongs to the kingdom of Euryarchaeota and is grouped with the Methanomicrobiales/extremehalophiles cluster. A. fulgidus has been shown to contain the complete pathway for dissimilatory sulfate reduction known from Bacteria. ATP sulfurylase (MgATP-sulfate adenylyltransferase) is the key enzyme in dissimilatory and assimilatory sulfate reduction. It catalyzes the activation of inorganic sulfate by ATP to give pyrophosphate and adenosine 5'-phosphosulfate (APS), the shared intermediate in these two pathways. In dissimilatory sulfate reduction, APS reductase catalyzes the reduction of APS to AMP and sulfite, which is reduced to sulfide by sulfite reductase. Dissimilatory ATP sulfurylase has also been found in some chemotrophic and phototrophic sulfur-oxidizing bacteria in which it functions in the opposite direction, releasing sulfate and ATP from APS. Dissimilatory ATP sulfurylase have been isolated and characterized from A. fulgidus . The gene encoding this archaeal ATP sulfurylase has been cloned and expressed in Escherichia coli . However, the properties of the recombinant enzyme show significant differences to those of the native enzyme.