TY - JOUR
AB - <p>Gene transcription is a fundamental cellular process carried out by RNA polymerase (RNAP). Transcription initiation is highly regulated and in bacteria, transcription initiation is mediated by sigma factors, which recruit RNA polymerase (RNAP) to the promoter DNA region and facilitate open complex formation, where double stranded DNA is opening up into a transcription bubble and template strand DNA is in position for initial RNA synthesis. During initial transcription, DNA downstream of the transcription start site is fed into the active site of RNAP, whilst the upstream promoter DNA remains tethered to the RNAP via the sigma factor, resulting in a build-up of tension. In order to progress to the processive elongation state, RNAP must escape from the promoter, and displace or dissociate the sigma factor. Bacteria s factors can be broadly separated into two classes with the majority belong to the sigma70 class, represented by the sigma70 that regulate housekeeping genes. sigma54 forms a class on its own and regulate stress response genes. Extensive studies on sigma70 have revealed the molecular mechanisms of sigma70 promoter escape while how sigma54 transitions from initial transcription to elongation is unknown. Here we present a series of cryo electron microscopy structures of the sigma54 factor with progressively longer RNA, revealing the molecular mechanism of σ54 displacement and promoter escape. Our data show that the initial instability is driven by DNA scrunching, and the final displacement steps are driven by both RNA extension and DNA scrunching.</p>
TI - Structural Basis of σ54 Displacement and Promoter Escape in Bacterial Transcription
JF - bioRxiv
DO - 10.1101/2023.06.09.544244
DA - 2023-06-09
UR - https://www.deepdyve.com/lp/biorxiv/structural-basis-of-54-displacement-and-promoter-escape-in-bacterial-0hd04JuKax
SP - 2023.06.09.544244
DP - DeepDyve
ER -