Tungsten, the surprisingly positively acting heavy metal element for prokaryotes.

The history and changing function of tungsten as the heaviest element in biological systems is given. It starts from an inhibitory element/anion, especially for the iron molybdenum-cofactor (FeMoCo)-containing enzyme nitrogenase involved in dinitrogen fixation, as well as for the many "metal binding pterin" (MPT)-, also known as tricyclic pyranopterin- containing classic molybdoenzymes, such as the sulfite oxidase and the xanthine dehydrogenase family of enzymes. They are generally involved in the transformation of a variety of carbon-, nitrogen- and sulfur-containing compounds.

Identification and characterization of the cytoplasmic tungstate/molybdate-binding protein (Mop) from Eubacterium acidaminophilum.

The mop gene, encoding the molybdate-binding protein from Eubacterium acidaminophilum, was cloned using Clostridium pasteurianum mopI as a probe for heterologous hybridization. mop encodes a 69-amino-acid protein ( M(r) 7,328) with high sequence similarities to members of the molbindin protein family, which have been implicated in molybdenum storage and homeostasis. Northern blot analysis showed three mRNA transcripts (1.