Identification of a Transcription Factor that Represses Alkane Hydroxylase Expression

Abstract

Some gram negative and gram positive bacteria have evolved enzymes for metabolizing alkanes. A medium‐chain alkane hydroxylase has been found in the model organism Caulobacter crescentus, belonging to the CYP153 family of cytochrome P450 enzymes. However, the molecular mechanisms regulating expression of this enzyme are still unknown. We carried out a reverse genetics screen and RNA‐seq to identify CoxR as a transcription factor regulating this alkane hydroxylase. A deletion of coxR resulted in upregulation of both the alkane hydroxylase as well as ferredoxin and ferredoxin reductase enzymes. EMSA assays showed that CoxR bound directly to a short region of the alkane hydroxylase promoter. In summary, we have identified a novel transcription factor involved in metabolism of alkanes.