Bacterial promoters triggering biodegradation of aromatic pollutants

Unraveling the complex transcriptional regulation of bacterial catabolism o f aromatic pollutants is a prerequisite for engineering efficient biologica l systems for many biotechnological applications. A first level of regulati on relies on specific regulator-promoter pairs. There have been new insight s into the molecular mechanisms that regulatory proteins use to sense a giv en signal and to activate transcription initiation from the cognate promote rs. A second level of regulation allows adjustment of the expression of the particular catabolic operons in response to the global environmental condi tions of the cells, and recent findings provide some clues about the mechan isms underlying such complex regulatory checkpoints.