Endogenous H2O2 produced by Streptococcus pneumoniae controls FabF activity

►Endogenous H2O2 produced by Streptococcus pneumoniae inhibits FabF activity by oxidizing its active site cysteine-thiol residue. ►Inhibition of FabF activity results in a significant change in membrane fatty acid composition, mainly: decreased proportions of long, unsaturated fatty acyl chains. ►The decrease in the proportions of long, unsaturated fatty acyl chains induces the transcription of FASII genes. ►The present study provides evidence showing that H2O2 produced by S. pneumoniae serves as a beneficial molecular signal, allowing the attenuation of FabF activity, to enable membrane adaptation at various growth conditions.