Transcriptional organization and dynamic expression of the hbpCAD genes, which encode the first three enzymes for 2-hydroxybiphenyl degradation in Pseudomonas azelaica HBP1

Two operons of the hbpCAD gene cluster are independently regulated and their expression is mediated by HbpR protein, which requires RNA polymerase-sigma(sup)54 and an integration host factor for complete activation. The transcriptional organization of the gene cluster facilitates orderly expression of the hbp genes and 2-hydroxybiphenyl degradation pathway.