Inhibition of Bacterial Gene Transcription with an RpoN-Based Stapled Peptide.

In response to environmental and other stresses, the σ54 subunit of bacterial RNA polymerase (RNAP) controls expression of several genes that play a significant role in the virulence of both plant and animal pathogens. Recruitment of σ54 to RNAP initiates promoter-specific transcription via the double-stranded DNA denaturation mechanism of the cofactor. The RpoN box, a recognition helix found in the C-terminal region of σ54, has been identified as the component necessary for major groove insertion at the -24 position of the promoter. We employed the hydrocarbon stapled peptide methodology to design and synthesize stapled σ54 peptides capable of penetrating Gram-negative bacteria, binding the σ54 promoter, and blocking the interaction between endogenous σ54 and its target DNA sequence, thereby reducing transcription and activation of σ54 response genes. Published by Elsevier Ltd.