title: Polyribonucleotide phosphorylase is a double-stranded DNA-binding protein.
abstract: Polyribonucleotide phosphorylase (PNPase) is one of the critical components of the E. coli RNA degradosome, which consists of both PNPase and endoribonuclease RNase E. The function of this complex is to control the rate of mRNA degradation. The PNPase possesses two enzymatic activities, namely 3'-5' processive exoribonuclease activity and 5'-3' RNA polymerase activity. In the present study, we used conventional chromatography to purify an E. coli protein that binds to a specific double-stranded DNA sequence. Microsequencing of the purified protein showed that this DNA-binding protein was PNPase. Our data further demonstrate that PNPase binds to DNA in a sequence-specific manner. These data suggest that PNPase may have previously unappreciated DNA-related functions in addition to its known role in mRNA degradation.
authors.affiliation: Department of Obstetrics, Gynecology and Reproductive Sciences, The Reproductive Endocrinology Center, University of California, San Francisco 94143-0556, USA.
authors.forename: P
authors.initials: P
authors.lastname: Zhang
authors.forename: J L
authors.initials: JL
authors.lastname: Vigne
authors.forename: S H
authors.initials: SH
authors.lastname: Mellon
mesh_terms: D000595:Amino Acid Sequence; D002852:Chromatography, Ion Exchange; D004269:DNA, Bacterial / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000302:isolation & purification / Q000378:metabolism*; D004926:Escherichia coli / Q000201:enzymology / Q000235:genetics; D008969:Molecular Sequence Data; D011117:Polyribonucleotide Nucleotidyltransferase / Q000302:isolation & purification / Q000378:metabolism*; D011485:Protein Binding
chemical_list: D004269:DNA, Bacterial; D004268:DNA-Binding Proteins; D011117:Polyribonucleotide Nucleotidyltransferase