DksA-DnaJ redox interactions provide a signal for the activation of bacterial RNA polymerase.

ABSTRACT: RNA polymerase is the only known protein partner of the transcriptional regulator DksA. Herein, we demonstrate that the chaperone DnaJ establishes direct, redox-based interactions with oxidized DksA. Cysteine residues in the zinc finger of DksA become oxidized in Salmonella exposed to low concentrations of hydrogen peroxide (H₂O₂). The resulting disulfide bonds unfold the globular domain of DksA, signaling high-affinity interaction of the C-terminal α-helix to DnaJ. Oxidoreductase and chaperone activities of DnaJ reduce the disulfide bonds of its client and promote productive interactions between DksA and RNA polymerase. Simultaneously, guanosine tetraphosphate (ppGpp), which is synthesized by RelA in response to low concentrations of H₂O₂

SUBMITTER: Kim JS 

PROVIDER: S-EPMC6294903 | biostudies-literature | 2018 Dec

REPOSITORIES: biostudies-literature