US EPA

1750718 

Journal Article 

A selenium-dependent and a selenium-independent formylmethanofuran dehydrogenase and their transcriptional regulation in the hyperthermophilic Methanopyrus kandleri 

Vorholt, JA; Vaupel, M; Thauer, RK 

1997 

1 

Molecular Microbiology
ISSN: 0950-382X 

23 

5 

1033-1042 

English 

9076739 

10.1046/j.1365-2958.1997.2931653.x 

WOS:A1997WL76400017 

The genome of Methanopyrus kandleri was found to harbour a gene, fwuB, predicted to encode the catalytic subunit of a tungsten formylmethanofuran dehydrogenase with an active site selenocysteine, and a second gene, fwcB, encoding a tungsten formylmethanofuran dehydrogenase with an active site cysteine. Northern blot and primer-extension analysis revealed that both genes were differentially transcribed. During growth of the methanogen on medium supplemented with selenium only fwuB was transcribed, whereas transcription of both fwuB and fwcB was observed on selenium-deprived medium. Growth of M. kandleri was stimulated by tungstate and selenite but not by molybdate. The findings indicate that the hyperthermophilic archaeon contains two tungsten isoenzymes of formylmethanofuran dehydrogenase, one of which is a novel selenium enzyme. They also indicate that the hyperthermophilic methanogen probably does not contain a molybdenum formylmethanofuran dehydrogenase which appears to be present only in thermophilic and mesophilic methanogens. 

Aldehyde Oxidoreductases/genetics; Amino Acid Sequence; Base Sequence; Blotting, Northern; Cell Extracts/analysis; Chromosome Mapping; Cloning, Molecular; Cysteine/genetics; DNA Primers; DNA, Bacterial/genetics; Euryarchaeota/enzymology/genetics/growth & development; Gene Expression Regulation, Bacterial; Gene Expression Regulation, Enzymologic; Isoenzymes/genetics; Molecular Sequence Data; Molybdenum/pharmacology; Selenium/metabolism; Selenocysteine/genetics; Sequence Alignment; Sodium Selenite/pharmacology; Transcription, Genetic; Tungsten/metabolism; Tungsten Compounds/pharmacology