The transcription bubble of the RNA polymerase-promoter open complex exhibits conformational heterogeneity and millisecond-scale dynamics: implications for transcription start-site selection.

ABSTRACT: Bacterial transcription is initiated after RNA polymerase (RNAP) binds to promoter DNA, melts ~14 bp around the transcription start site and forms a single-stranded "transcription bubble" within a catalytically active RNAP-DNA open complex (RP(o)). There is significant flexibility in the transcription start site, which causes variable spacing between the promoter elements and the start site; this in turn causes differences in the length and sequence at the 5' end of RNA transcripts and can be important for gene regulation. The start-site variability also implies the presence of some flexibility in the positioning of the DNA relative to the RNAP active site in RP(o). The flexibility may occur in the positioning of the transcription bubble prior to RNA synthesis and may reflect bubble expans

SUBMITTER: Robb NC 

PROVIDER: S-EPMC3783996 | biostudies-literature | 2013 Mar

REPOSITORIES: biostudies-literature