A Newly Found Catabolite Responsive Element Plays a Bidirectional Role in Carbon Catabolism in Bacillus licheniformis

Bacillus licheniformis is widely used in producing various valuable products, such as food enzymes, industrial chemicals and biocides. The carbon catabolite regulation process in the utilization of raw materials is crucial to maximizing the efficiency of this microbial cell factory. Current understanding of the molecular mechanism of this regulation is based on limited motif patterns in protein-DNA recognition, where the typical catabolite responsive element (CRE) motif is ‘TGWNANCGNTNWCA’. Here, CRE Tre was identified and characterized as a new CRE. It consists of two palindrome arms of 6 nucleotides (AGCTTT/AAAGCT) and an intermediate spacer. CRE Tre is involved in a bidirectional regulation under the glucose stress environment. When AGCTTT appears in the 5’-end, the regulatory element exhibited a carbon catabolite activation (CCA) effect, while AAAGCT in the 5’-end corresponds to carbon catabolite repression (CCR). Further investigation indicated a wide occurrence of CRE Tre in the genome of B. licheniformis.