title: Modular organization of the catalytic center of RNA polymerase.
abstract: The Fe2+ ion that specifically replaces Mg2+ in the active center of RNA polymerase generates reactive hydroxyl radicals that cause highly localized cleavage of polypeptide chains. Mapping of the cleavage sites revealed the overall architecture of the active center. Nine distinct sites, five in the beta subunit and four in the beta' subunit of Escherichia coli RNA polymerase, all at or near highly conserved sequence motifs, are brought together in the enzyme's ternary structure within the distance of approximately 1 nm from the active center Me2+. These sites are located in at least six different domains of the subunits, reflecting modular organization of the active center.
authors.affiliation: Public Health Research Institute, 455 First Avenue, New York, NY 10016, USA.
authors.forename: A
authors.initials: A
authors.lastname: Mustaev
authors.forename: M
authors.initials: M
authors.lastname: Kozlov
authors.forename: V
authors.initials: V
authors.lastname: Markovtsov
authors.forename: E
authors.initials: E
authors.lastname: Zaychikov
authors.forename: L
authors.initials: L
authors.lastname: Denissova
authors.forename: A
authors.initials: A
authors.lastname: Goldfarb
mesh_terms: D000595:Amino Acid Sequence; D001665:Binding Sites; D012321:DNA-Directed RNA Polymerases / Q000737:chemistry* / Q000235:genetics; D004926:Escherichia coli / Q000201:enzymology*; D007501:Iron; D008969:Molecular Sequence Data; D010449:Peptide Mapping; D017421:Sequence Analysis
chemical_list: D007501:Iron; D012321:DNA-Directed RNA Polymerases