title: Inhibition of the action of Escherichia coli transcription termination protein rho by poly(C) and heparin.
abstract: Poly(C) and heparin at low concentrations (1 microgram/ml) prevent the RNA synthesis termination protein rho from functioning during the biosynthesis of RNA from bacteriophage T7 DNA catalyzed by Escherichia coli RNA polymerase. Both of these polyanions inhibit the binding of rho to isolated T7 RNA. Heparin also inhibits rho ATPase when isolated RNA transcripts are used as cofactors. It is concluded that the polyanions inhibit termination by binding to the site on rho that is normally used for the initial interaction with a nascent RNA transcript in the rho-mediated release of RNA. Since one of the inhibitors, poly(C), is itself a potent activator for rho ATPase, it is also concluded that the ATP hydrolysis step that is required for rho termination has to be coupled to an action of rho on the RNA molecule to be released from the transcription complex.
mesh_terms: D000251:Adenosine Triphosphatases / Q000037:antagonists & inhibitors; D010582:Bacteriophage lambda; D012321:DNA-Directed RNA Polymerases / Q000378:metabolism; D004926:Escherichia coli / Q000032:analysis; D006493:Heparin / Q000494:pharmacology*; D011066:Poly C / Q000494:pharmacology*; D011131:Polyribonucleotides / Q000494:pharmacology*; D012367:RNA, Viral / Q000096:biosynthesis; D012234:Rho Factor / Q000037:antagonists & inhibitors*; D013604:T-Phages; D014157:Transcription Factors / Q000037:antagonists & inhibitors*
chemical_list: D011131:Polyribonucleotides; D012367:RNA, Viral; D012234:Rho Factor; D014157:Transcription Factors; D011066:Poly C; D006493:Heparin; D012321:DNA-Directed RNA Polymerases; D000251:Adenosine Triphosphatases; C031715:rho-ATPase