Direct interactions between the coiled-coil tip of DksA and the trigger loop of RNA polymerase mediate transcriptional regulation.

ABSTRACT: Escherichia coli DksA is a transcription factor that binds to RNA polymerase (RNAP) without binding to DNA, destabilizing RNAP-promoter interactions, sensitizing RNAP to the global regulator ppGpp, and regulating transcription of several hundred target genes, including those encoding rRNA. Previously, we described promoter sequences and kinetic properties that account for DksA's promoter specificity, but how DksA exerts its effects on RNAP has remained unclear. To better understand DksA's mechanism of action, we incorporated benzoyl-phenylalanine at specific positions in DksA and mapped its cross-links to RNAP, constraining computational docking of the two proteins. The resulting evidence-based model of the DksA-RNAP complex as well as additional genetic and biochemical approaches confirme

SUBMITTER: Lennon CW 

PROVIDER: S-EPMC3521624 | biostudies-literature | 2012 Dec

REPOSITORIES: biostudies-literature