Active site opening and closure control translocation of multisubunit RNA polymerase.

ABSTRACT: Multisubunit RNA polymerase (RNAP) is the central information-processing enzyme in all cellular life forms, yet its mechanism of translocation along the DNA molecule remains conjectural. Here, we report direct monitoring of bacterial RNAP translocation following the addition of a single nucleotide. Time-resolved measurements demonstrated that translocation is delayed relative to nucleotide incorporation and occurs shortly after or concurrently with pyrophosphate release. An investigation of translocation equilibrium suggested that the strength of interactions between RNA 3' nucleotide and nucleophilic and substrate sites determines the translocation state of transcription elongation complexes, whereas active site opening and closure modulate the affinity of the substrate site, thereby favo

SUBMITTER: Malinen AM 

PROVIDER: S-EPMC3424550 | biostudies-literature | 2012 Aug

REPOSITORIES: biostudies-literature