The MerR/NmlR Family Transcription Factor of Streptococcus pneumoniae responds to carbonyl stress and modulates hydrogen peroxide production

Abstract

The NmlRsp transcription factor of Streptococcus pneumoniae is shown to induce adhC (alcohol dehydrogenase) expression in the presence of both formaldehyde and methylglyoxal. nmlRsp and adhC mutant strains display altered and opposite aerobic growth phenotypes. The nmlRsp strain exhibits increased resistance to high oxygen tension, attributable to decreased H2O2 production, which correlated with downregulation of carbamoyl phosphate synthase (carB). This indicates a possible role for AdhC in aldehyde metabolism and a broader role for NmlRsp in the regulation of carbon metabolism.