title: A protein complex mediating mRNA degradation in Escherichia coli.
abstract: mRNA degradation in Escherichia coli is mediated by a combination of exo- and endoribonucleases. We present evidence for a multiprotein complex which includes at least two enzymes that play important roles in mRNA degradation: the exoribonuclease polynucleotide phosphorylase (PNPase) and the endoribonuclease RNase E. An activity which impedes the processive activity of PNPase at stem-loop structures also appears to be associated with the complex. This complex is estimated to have a molecular mass of about 500 kDa and includes several additional polypeptides whose functions are unknown. The identification of a complex which includes several activities associated with mRNA degradation has implications for the mechanisms and co-ordinated control of mRNA degradation.
authors.affiliation: Imperial Cancer Research Fund Laboratories, Institute of Molecular Medicine, Oxford, UK.
authors.forename: B
authors.initials: B
authors.lastname: Py
authors.forename: H
authors.initials: H
authors.lastname: Causton
authors.forename: E A
authors.initials: EA
authors.lastname: Mudd
authors.forename: C F
authors.initials: CF
authors.lastname: Higgins
mesh_terms: D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D001483:Base Sequence; D003593:Cytoplasm / Q000378:metabolism; D004269:DNA, Bacterial / Q000235:genetics; D004722:Endoribonucleases / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism; D004926:Escherichia coli / Q000235:genetics / Q000378:metabolism* / Q000648:ultrastructure; D016253:Microscopy, Immunoelectron; D008969:Molecular Sequence Data; D009097:Multienzyme Complexes / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism; D011117:Polyribonucleotide Nucleotidyltransferase / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism; D012323:RNA Processing, Post-Transcriptional; D012333:RNA, Messenger / Q000378:metabolism*; D016601:RNA-Binding Proteins / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism
chemical_list: D001426:Bacterial Proteins; D004269:DNA, Bacterial; D009097:Multienzyme Complexes; D012333:RNA, Messenger; D016601:RNA-Binding Proteins; D011117:Polyribonucleotide Nucleotidyltransferase; D004722:Endoribonucleases; C022537:ribonuclease E