RNA polymerase. Direct evidence for a unique topographical site for initiation.
The compound 9-(3'-azido-3'-deoxy-beta-D-xylofuranosyl)adenine 5'-monophosphate is an inhibitor (Ki = 330 microM) of the initiation binding site of the DNA-dependent RNA polymerase derived from Escherichia coli. The alpha-32P derivative of this photo-labile compound is used to derivatize a site on the sigma subunit of the holoenzyme (E sigma) using either T7 delta D111 or poly[d(A-T)] as a DNA template. The incorporation of the 32P label into the sigma subunit could be prevented by the addition of either 5'-AMP or 5'-ATP. The results are suggested to support the existence of a unique initiation binding site, topographically distinct from the sites employed during the elongation phase.
D001665:Binding Sites; D002851:Chromatography, High Pressure Liquid; D012321:DNA-Directed RNA Polymerases / Q000037:antagonists & inhibitors*; D003838:Deoxyadenine Nucleotides / Q000032:analysis; D004926:Escherichia coli / Q000201:enzymology*; D007700:Kinetics; D010446:Peptide Fragments / Q000032:analysis; D010761:Phosphorus Radioisotopes; D011485:Protein Binding
D003838:Deoxyadenine Nucleotides; D010446:Peptide Fragments; D010761:Phosphorus Radioisotopes; C047462:9-(3'-azido-3'-deoxyxylofuranosyl)adenine 5'-monophosphate; C042016:9-(3'-azido-3'-deoxy-beta-D-xylofuranosyl)adenine 5'-triphosphate; D012321:DNA-Directed RNA Polymerases