title: Translocation by multi-subunit RNA polymerases.
abstract: DNA template and RNA/DNA hybrid movement through RNA polymerase (RNAP) is referred to as "translocation". Because nucleic acid movement is coupled to NTP loading, pyrophosphate release, and conformational changes, the precise ordering of events during bond addition is consequential. Moreover, based on several lines of experimental evidence, translocation, pyrophosphate release or an associated conformational change may determine the transcription elongation rate. In this review we discuss various models of translocation, the data supporting the hypothesis that translocation rate determines transcription elongation rate and also data that may be inconsistent with this point of view. A model of the nucleotide addition cycle accommodating available experimental data is proposed. On the basis of this model, the molecular mechanisms regulating translocation and potential routes for NTP entry are discussed.
authors.affiliation: National Cancer Institute-Frederick, Frederick, MD 21702-1201, USA.
authors.forename: Maria
authors.initials: M
authors.lastname: Kireeva
authors.forename: Mikhail
authors.initials: M
authors.lastname: Kashlev
authors.forename: Zachary F
authors.initials: ZF
authors.lastname: Burton
mesh_terms: D000494:Allosteric Regulation; D001693:Biological Transport, Active; D020134:Catalytic Domain; D012321:DNA-Directed RNA Polymerases / Q000737:chemistry* / Q000378:metabolism*; D008958:Models, Molecular; D009711:Nucleotides / Q000378:metabolism; D011487:Protein Conformation; D021122:Protein Subunits; D013816:Thermodynamics
chemical_list: D009711:Nucleotides; D021122:Protein Subunits; D012321:DNA-Directed RNA Polymerases