title: A new subfamily of polyphosphate kinase 2 (class III PPK2) catalyzes both nucleoside monophosphate phosphorylation and nucleoside diphosphate phosphorylation.
abstract: Inorganic polyphosphate (polyP) is a linear polymer of tens to hundreds of phosphate (Pi) residues linked by "high-energy" phosphoanhydride bonds as in ATP. PolyP kinases, responsible for the synthesis and utilization of polyP, are divided into two families (PPK1 and PPK2) due to differences in amino acid sequence and kinetic properties. PPK2 catalyzes preferentially polyP-driven nucleotide phosphorylation (utilization of polyP), which is important for the survival of microbial cells under conditions of stress or pathogenesis. Phylogenetic analysis suggested that the PPK2 family could be divided into three subfamilies (classes I, II, and III). Class I and II PPK2s catalyze nucleoside diphosphate and nucleoside monophosphate phosphorylation, respectively. Here, we demonstrated that class III PPK2 catalyzes both nucleoside monophosphate and nucleoside diphosphate phosphorylation, thereby enabling us to synthesize ATP from AMP by a single enzyme. Moreover, class III PPK2 showed broad substrate specificity over purine and pyrimidine bases. This is the first demonstration that class III PPK2 possesses both class I and II activities.
authors: Department of Molecular Biotechnology, Graduate School of Advanced Sciences of Matter, Hiroshima University, Higashi-Hiroshima, Hiroshima, Japan.
authors: Kei
authors: K
authors: Motomura
authors: Ryuichi
authors: R
authors: Hirota
authors: Mai
authors: M
authors: Okada
authors: Takeshi
authors: T
authors: Ikeda
authors: Takenori
authors: T
authors: Ishida
authors: Akio
authors: A
authors: Kuroda
mesh_terms: D001419:Bacteria / Q000201:enzymology; D009702:Nucleoside Diphosphate Sugars / Q000378:metabolism*; D009712:Nucleotides, Cyclic / Q000378:metabolism*; D010766:Phosphorylation; D017856:Phosphotransferases (Phosphate Group Acceptor) / Q000302:isolation & purification / Q000378:metabolism*; D013379:Substrate Specificity
chemical_list: D009702:Nucleoside Diphosphate Sugars; D009712:Nucleotides, Cyclic; C019509:nucleoside monophosphate sugars; D017856:Phosphotransferases (Phosphate Group Acceptor); C022424:polyphosphate kinase