title: Regulation of Escherichia coli polynucleotide phosphorylase by ATP.
abstract: Polynucleotide phosphorylase (PNPase), an enzyme conserved in bacteria and eukaryotic organelles, processively catalyzes the phosphorolysis of RNA, releasing nucleotide diphosphates, and the reverse polymerization reaction. In Escherichia coli, both reactions are implicated in RNA decay, as addition of either poly(A) or heteropolymeric tails targets RNA to degradation. PNPase may also be associated with the RNA degradosome, a heteromultimeric protein machine that can degrade highly structured RNA. Here, we report that ATP binds to PNPase and allosterically inhibits both its phosphorolytic and polymerization activities. Our data suggest that PNPase-dependent RNA tailing and degradation occur mainly at low ATP concentrations, whereas other enzymes may play a more significant role at high energy charge. These findings connect RNA turnover with the energy charge of the cell and highlight unforeseen metabolic roles of PNPase.
authors.affiliation: Dipartimento di Biotecnologie e Bioscienze, Università degli Studi di Milano-Bicocca, 20126 Milan, Italy.
authors.forename: Marta
authors.initials: M
authors.lastname: Del Favero
authors.affiliation: Dipartimento di Biotecnologie e Bioscienze, Università degli Studi di Milano-Bicocca, 20126 Milan, Italy.
authors.forename: Elisa
authors.initials: E
authors.lastname: Mazzantini
authors.affiliation: Dipartimento di Scienze Biomolecolari e Biotecnologie, Università degli Studi di Milano, 20133 Milan, Italy.
authors.forename: Federica
authors.initials: F
authors.lastname: Briani
authors.affiliation: Centro di Studio del Consiglio Nazionale delle Ricerche sulla Biologia Cellulare e Molecolare delle Piante, 20133 Milan, Italy.
authors.forename: Sandro
authors.initials: S
authors.lastname: Zangrossi
authors.affiliation: Dipartimento di Biotecnologie e Bioscienze, Università degli Studi di Milano-Bicocca, 20126 Milan, Italy.
authors.forename: Paolo
authors.initials: P
authors.lastname: Tortora
authors.affiliation: Dipartimento di Scienze Biomolecolari e Biotecnologie, Università degli Studi di Milano, 20133 Milan, Italy. Electronic address: gianni.deho@unimi.it.
authors.forename: Gianni
authors.initials: G
authors.lastname: Dehò
mesh_terms: D000255:Adenosine Triphosphate / Q000235:genetics / Q000378:metabolism*; D000494:Allosteric Regulation / Q000502:physiology; D004926:Escherichia coli / Q000201:enzymology* / Q000235:genetics; D011117:Polyribonucleotide Nucleotidyltransferase / Q000235:genetics / Q000378:metabolism*; D020871:RNA Stability / Q000502:physiology*; D012329:RNA, Bacterial / Q000235:genetics / Q000378:metabolism*
chemical_list: D012329:RNA, Bacterial; D000255:Adenosine Triphosphate; D011117:Polyribonucleotide Nucleotidyltransferase