title: The identification of a novel protein involved in molybdenum cofactor biosynthesis in Escherichia coli.
abstract: In the second step of the molybdenum cofactor (Moco) biosynthesis in Escherichia coli, the l-cysteine desulfurase IscS was identified as the primary sulfur donor for the formation of the thiocarboxylate on the small subunit (MoaD) of MPT synthase, which catalyzes the conversion of cyclic pyranopterin monophosphate to molybdopterin (MPT). Although in Moco biosynthesis in humans, the thiocarboxylation of the corresponding MoaD homolog involves two sulfurtransferases, an l-cysteine desulfurase, and a rhodanese-like protein, the rhodanese-like protein in E. coli remained enigmatic so far. Using a reverse approach, we identified a so far unknown sulfurtransferase for the MoeB-MoaD complex by protein-protein interactions. We show that YnjE, a three-domain rhodanese-like protein from E. coli, interacts with MoeB possibly for sulfur transfer to MoaD. The E. coli IscS protein was shown to specifically interact with YnjE for the formation of the persulfide group on YnjE. In a defined in vitro system consisting of MPT synthase, MoeB, Mg-ATP, IscS, and l-cysteine, YnjE was shown to enhance the rate of the conversion of added cyclic pyranopterin monophosphate to MPT. However, YnjE was not an enhancer of the cysteine desulfurase activity of IscS. This is the first report identifying the rhodanese-like protein YnjE as being involved in Moco biosynthesis in E. coli. We believe that the role of YnjE is to make the sulfur transfer from IscS for Moco biosynthesis more specific because IscS is involved in a variety of different sulfur transfer reactions in the cell.
authors.affiliation: Institute of Biochemistry and Biology, University of Potsdam, Potsdam, Germany.
authors.forename: Jan-Ulrik
authors.initials: JU
authors.lastname: Dahl
authors.affiliation: Institute of Biochemistry and Biology, University of Potsdam, Potsdam, Germany.
authors.forename: Alexander
authors.initials: A
authors.lastname: Urban
authors.affiliation: Institute of Biochemistry and Biology, University of Potsdam, Potsdam, Germany.
authors.forename: Andrea
authors.initials: A
authors.lastname: Bolte
authors.affiliation: Department of Biochemistry, Virginia Tech, Blacksburg, Virginia 24061.
authors.forename: Promjit
authors.initials: P
authors.lastname: Sriyabhaya
authors.affiliation: Department of Biochemistry, Virginia Tech, Blacksburg, Virginia 24061.
authors.forename: Janet L
authors.initials: JL
authors.lastname: Donahue
authors.affiliation: Helmholtz Center for Infection Research, 38124 Braunschweig, Germany.
authors.forename: Manfred
authors.initials: M
authors.lastname: Nimtz
authors.affiliation: Department of Biochemistry, Virginia Tech, Blacksburg, Virginia 24061.
authors.forename: Timothy J
authors.initials: TJ
authors.lastname: Larson
authors.affiliation: Institute of Biochemistry and Biology, University of Potsdam, Potsdam, Germany. Electronic address: sleim@uni-potsdam.de.
authors.forename: Silke
authors.initials: S
authors.lastname: Leimkühler
mesh_terms: D013437:Carbon-Sulfur Lyases / Q000235:genetics / Q000378:metabolism*; D003067:Coenzymes / Q000096:biosynthesis* / Q000235:genetics; D004926:Escherichia coli / Q000235:genetics / Q000378:metabolism*; D029968:Escherichia coli Proteins / Q000235:genetics / Q000378:metabolism*; D006801:Humans; D008667:Metalloproteins / Q000096:biosynthesis* / Q000235:genetics; D000090006:Molybdenum Cofactors; D009713:Nucleotidyltransferases / Q000235:genetics / Q000378:metabolism; D011621:Pteridines; D013466:Sulfurtransferases / Q000235:genetics / Q000378:metabolism*
chemical_list: D013437:Carbon-Sulfur Lyases; D003067:Coenzymes; D029968:Escherichia coli Proteins; D008667:Metalloproteins; D000090006:Molybdenum Cofactors; D009713:Nucleotidyltransferases; D011621:Pteridines; D013466:Sulfurtransferases; C022261:molybdopterin; C499585:MoeB protein, E coli; C547509:YnjE protein, E coli; C085585:molybdopterin synthase; C080546:cysteine desulfurase