title: Binding of transcription termination protein nun to nascent RNA and template DNA.
abstract: The amino-terminal arginine-rich motif of coliphage HK022 Nun binds phage lambda nascent transcript, whereas the carboxyl-terminal domain interacts with RNA polymerase (RNAP) and blocks transcription elongation. RNA binding is inhibited by zinc (Zn2+) and stimulated by Escherichia coli NusA. To study these interactions, the Nun carboxyl terminus was extended by a cysteine residue conjugated to a photochemical cross-linker. The carboxyl terminus contacted NusA and made Zn2+-dependent intramolecular contacts. When Nun was added to a paused transcription elongation complex, it cross-linked to the DNA template. Nun may arrest transcription by anchoring RNAP to DNA.
authors.affiliation: Department of Biochemistry and Molecular Biophysics and Institute of Cancer Research, Columbia University, New York, NY 10032, USA.
authors.forename: R S
authors.initials: RS
authors.lastname: Watnick
authors.forename: M E
authors.initials: ME
authors.lastname: Gottesman
mesh_terms: D000595:Amino Acid Sequence; D001386:Azides; D001426:Bacterial Proteins / Q000378:metabolism; D010582:Bacteriophage lambda / Q000235:genetics / Q000502:physiology; D003432:Cross-Linking Reagents; D004279:DNA, Viral / Q000378:metabolism*; D012321:DNA-Directed RNA Polymerases / Q000378:metabolism; D004229:Dithiothreitol / Q000494:pharmacology; D004926:Escherichia coli / Q000201:enzymology / Q000821:virology; D029968:Escherichia coli Proteins; D008969:Molecular Sequence Data; D010445:Peptide Elongation Factors; D010618:Phenanthrolines / Q000378:metabolism; D011485:Protein Binding; D011725:Pyridines; D012333:RNA, Messenger / Q000378:metabolism*; D012367:RNA, Viral / Q000378:metabolism; D013698:Templates, Genetic; D014157:Transcription Factors / Q000737:chemistry / Q000378:metabolism*; D014158:Transcription, Genetic; D035602:Transcriptional Elongation Factors; D010948:Viral Plaque Assay; D014764:Viral Proteins / Q000737:chemistry / Q000378:metabolism*; D015032:Zinc / Q000494:pharmacology
chemical_list: C088903:5-iodoacetamido-1,10-phenanthroline; D001386:Azides; D001426:Bacterial Proteins; D003432:Cross-Linking Reagents; D004279:DNA, Viral; D029968:Escherichia coli Proteins; C073501:Nun protein, Enterobacteria phage HK022; D010445:Peptide Elongation Factors; D010618:Phenanthrolines; D011725:Pyridines; D012333:RNA, Messenger; D012367:RNA, Viral; D014157:Transcription Factors; D035602:Transcriptional Elongation Factors; D014764:Viral Proteins; C402646:iodo-N-((2-pyridyldithio)ethyl)-4-azidosalicylamide; C068727:nusA protein, E coli; D012321:DNA-Directed RNA Polymerases; D015032:Zinc; D004229:Dithiothreitol