Tungsten biochemistry of Pyrococcus furiosus

Tungsten is the heaviest element that exhibits biological activity (atomic number 74), when it is present in an enzyme. It is taken up by cells in the form of tungstate, and it is subsequently processed into an organic cofactor referred to as tungstopterin, which is found as active center in several enzymes. Pyrococcus furiosus is a hyperthermophilic archaeon that grows anaerobically at an optimal temperature of 100 ËšC, strictly dependent on the presence of tungstate. Over the last years, P. furiosus has become a model organism for hyperthermophiles, as many of its proteins have been the subject of research and its genome has been sequenced. Also regarding tungsten metabolism P. furiosus can be considered as a model: four tungsten containing aldehyde oxidoreductases were already characterized in some detail before the initiation of this study. In this thesis several aspects of tungsten metabolism in P. furiosus have been further explored: its tungstate transport system has been identified and characterized (WtpABC), studies on aspects of tungsten cofactor biosynthesis have been carried out and a new tungsten-containing aldehyde oxidoreductase (AOR), WOR5, has been purified and characterized.Applied Science