Mechanism of sequence-specific pausing of bacterial RNA polymerase.

ABSTRACT: Sequence-specific pausing of multisubunit RNA polymerases (RNAPs) represents a rate-limiting step during transcription elongation. Pausing occurs on average every 100 bases of DNA. Several models have been proposed to explain pausing, including backtracking of the ternary elongation complex, delay of translocation of the enzyme along DNA, or a conformational change in the active site preventing formation of the phosphodiester bond. Here, we performed biochemical characterization of previously-reported pauses of Escherichia coli RNAP and found that they are not associated with backtracking or a translocation delay. Instead, the paused complex contains the 3' end of the transcript in the active center and is capable of binding the next cognate NTP. However, bond formation occurs much slower

SUBMITTER: Kireeva ML 

PROVIDER: S-EPMC2690050 | biostudies-literature | 2009 Jun

REPOSITORIES: biostudies-literature