Translocation by multi-subunit RNA polymerases

Biochim Biophys Acta. May-Jun 2010;1799(5-6):389-401. doi: 10.1016/j.bbagrm.2010.01.007. Epub 2010 Jan 25.

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.

Publication types

  • Research Support, Non-U.S. Gov't
  • Review

MeSH terms

  • Allosteric Regulation
  • Biological Transport, Active
  • Catalytic Domain
  • DNA-Directed RNA Polymerases / chemistry*
  • DNA-Directed RNA Polymerases / metabolism*
  • Models, Molecular
  • Nucleotides / metabolism
  • Protein Conformation
  • Protein Subunits
  • Thermodynamics

Substances

  • Nucleotides
  • Protein Subunits
  • DNA-Directed RNA Polymerases