Activation of Bacillus subtilis Ugd by the BY-Kinase PtkA Proceeds via Phosphorylation of Its Residue Tyrosine 70

Publication: Research - peer-reviewJournal article – Annual report year: 2009

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The phosphorylation-dependent activation of bacterial UDP-glucose dehydrogenases by BY-kinases has been previously described in several bacterial model organisms, but the identity of phosphorylated tyrosine(s) and the exact activation mechanism remained unknown. A recent site-specific phosphoproteomic study indicated that tyrosine 70 is phosphorylated in the Bacillus subtilis UDP-glucose dehydrogenase Ugd. In this study we confirm that this tyrosine 70 is indeed the main residue phosphorylated by the cognate BY-kinase PtkA. Homology-based modeling of the Ugd structure using structures from UDP-glucose/GDP-mannose dehydrogenases revealed that this residue is in close proximity to the NAD-binding site. We identified lysine 108 as the second important residue involved in Ugd activation. Enzymatic characterization of the Ugd proteins mutated in residues tyrosine 70 or lysine 108 suggested a phosphorylation-based regulatory mechanism. This study represents the first attempt to understand the activation of a bacterial enzyme by tyrosine phosphorylation at the molecular level.
Original languageEnglish
JournalJournal of Molecular Microbiology and Biotechnology
Issue number2
Pages (from-to)83-89
StatePublished - 2009
CitationsWeb of Science® Times Cited: 22


  • Tyrosine phosphorylation, Enzyme activity, UDP-glucose dehydrogenase, Kinase
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ID: 3575273