title: Structural perspective on mutations affecting the function of multisubunit RNA polymerases.
abstract: High-resolution crystallographic structures of multisubunit RNA polymerases (RNAPs) have increased our understanding of transcriptional mechanisms. Based on a thorough review of the literature, we have compiled the mutations affecting the function of multisubunit RNA polymerases, many of which having been generated and studied prior to the publication of the first high-resolution structure, and highlighted the positions of the altered amino acids in the structures of both the prokaryotic and eukaryotic enzymes. The observations support many previous hypotheses on the transcriptional process, including the implication of the bridge helix and the trigger loop in the processivity of RNAP, the importance of contacts between the RNAP jaw-lobe module and the downstream DNA in the establishment of a transcription bubble and selection of the transcription start site, the destabilizing effects of ppGpp on the open promoter complex, and the link between RNAP processivity and termination. This study also revealed novel, remarkable features of the RNA polymerase catalytic mechanisms that will require additional investigation, including the putative roles of fork loop 2 in the establishment of a transcription bubble, the trigger loop in start site selection, and the uncharacterized funnel domain in RNAP processivity.
authors.affiliation: Gene Transcription Laboratory, Institut de Recherches Cliniques de Montréal, 110 Ave. des Pins Ouest, Montréal, Québec, Canada.
authors.forename: Vincent
authors.initials: V
authors.lastname: Trinh
authors.forename: Marie-France
authors.initials: MF
authors.lastname: Langelier
authors.forename: Jacques
authors.initials: J
authors.lastname: Archambault
authors.forename: Benoit
authors.initials: B
authors.lastname: Coulombe
mesh_terms: D019943:Amino Acid Substitution; D001426:Bacterial Proteins / Q000737:chemistry* / Q000235:genetics* / Q000378:metabolism; D012321:DNA-Directed RNA Polymerases / Q000737:chemistry* / Q000235:genetics* / Q000378:metabolism; D004351:Drug Resistance / Q000235:genetics; D005656:Fungal Proteins / Q000737:chemistry* / Q000235:genetics* / Q000378:metabolism; D009154:Mutation; D011487:Protein Conformation; D012319:RNA Polymerase II / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D024363:Transcription Initiation Site
chemical_list: D001426:Bacterial Proteins; D005656:Fungal Proteins; D012319:RNA Polymerase II; D012321:DNA-Directed RNA Polymerases