Probing the role of copper in the biosynthesis of the molybdenum cofactor in Escherichia coli and Rhodobacter sphaeroides.
The crystal structure of Cnx1G, an enzyme involved in the biosynthesis of the molybdenum cofactor (Moco) in Arabidopsis thaliana, revealed the remarkable feature of a copper ion bound to the dithiolene unit of a molybdopterin intermediate (Kuper et al. Nature 430:803-806, 2004). To characterize further the role of copper in Moco biosynthesis, we examined the in vivo and/or in vitro activity of two Moco-dependent enzymes, dimethyl sulfoxide reductase (DMSOR) and nitrate reductase (NR), from cells grown under a variety of copper conditions. We found the activities of DMSOR and NR were not affected when copper was depleted from the media of either Escherichia coli or Rhodobacter sphaeroides. These data suggest that while copper may be utilized during Moco biosynthesis when it is available, copper does not appear to be strictly required for Moco biosynthesis in these two organisms.
Department of Chemistry, University of Utah, 315 South 1400 East, Salt Lake City, UT 84112, USA.
M Scott
MS
Morrison
Paul A
PA
Cobine
Eric L
EL
Hegg
D001426:Bacterial Proteins / Q000032:analysis / Q000378:metabolism*; D003067:Coenzymes / Q000096:biosynthesis* / Q000737:chemistry; D003300:Copper / Q000378:metabolism* / Q000494:pharmacology; D004926:Escherichia coli / Q000187:drug effects / Q000201:enzymology*; D007506:Iron-Sulfur Proteins / Q000032:analysis / Q000187:drug effects / Q000378:metabolism*; D008667:Metalloproteins / Q000096:biosynthesis* / Q000737:chemistry; D000090006:Molybdenum Cofactors; D050901:Nitrate Reductase / Q000032:analysis / Q000187:drug effects / Q000378:metabolism*; D010088:Oxidoreductases / Q000032:analysis / Q000187:drug effects / Q000378:metabolism*; D011621:Pteridines / Q000737:chemistry; D012242:Rhodobacter sphaeroides / Q000187:drug effects / Q000201:enzymology*
D001426:Bacterial Proteins; D003067:Coenzymes; D003300:Copper; D007506:Iron-Sulfur Proteins; D008667:Metalloproteins; D000090006:Molybdenum Cofactors; D050901:Nitrate Reductase; D010088:Oxidoreductases; D011621:Pteridines; C022261:molybdopterin; C045664:dimethyl sulfoxide reductase