PexR is a noncanonical regulator of the peroxide stress response in bacteria.

ABSTRACT: Cells combat peroxide stress using peroxiredoxins and catalases. The paradigmatic H2O2-sensing OxyR or PerR transcription regulators typically control their expression in bacteria. Here, we report our discovery of a noncanonical mechanism for H2O2-signaled regulation of peroxiredoxin ahpC and catalase katB genes in Myxococcus xanthus by PexR, an ATP-binding bacterial enhancer binding protein that acts as a dual-function repressor-activator. PexR, a dimer capable of higher-order oligomerization, binds to dyad-symmetry repeats upstream of ahpC and katB, activating their H2O2-induced σ54-dependent expression. Under peroxide stress-free conditions, PexR downregulates housekeeping σA-dependent ahpC expression. Deleting ahpC causes pleiotropy, and synthetic lethality when eliminated with katB or

SUBMITTER: Bastida-Martinez E 

PROVIDER: S-EPMC12754779 | biostudies-literature | 2025 Nov

REPOSITORIES: biostudies-literature