An insertion in the catalytic trigger loop gates the secondary channel of RNA polymerase.

ABSTRACT: Escherichia coli DksA and GreB bind to RNA polymerase (RNAP), reaching inside the secondary channel, with similar affinities but have different cellular functions. DksA destabilizes promoter complexes whereas GreB facilitates RNA cleavage in arrested elongation complexes (ECs). Although the less abundant GreB may not interfere with DksA regulation during initiation, reports that DksA acts during elongation and termination suggest that it may exclude GreB from arrested complexes, potentially triggering genome instability. Here, we show that GreB does not compete with DksA during termination whereas DksA, even when present in several hundredfold molar excess, does not inhibit GreB-mediated cleavage of the nascent RNA. Our findings that DksA does not bind to backtracked or active ECs provide

SUBMITTER: Furman R 

PROVIDER: S-EPMC5522729 | biostudies-literature | 2013 Jan

REPOSITORIES: biostudies-literature