Characterization and modification of molecular mechanism for transcriptional regulation of the degradation enzyme system of an environmental pollutant

约氏红球菌RHA1是环境污染物多氯联苯(PCBS)的强降解剂。其降解酶的诱导需要诱导底物，并由两个双组分转录调控因子BphS1T1和BphS2T2进行。对BphS1T1和BphS2T2的转录调控机制进行了研究，以获得一株其降解多氯联苯的酶由多氯联苯本身诱导的菌株。在诱导底物存在的情况下，BphT(BphT1/T2)被磷酸化。降解酶基因操纵子启动子之间有一个新的24bp的共同序列，对BphST的转录诱导具有必要和充分的功能，这表明该序列是包括BphT在内的转录复合体的结合部位。

Rhodococcus jostii RHA1 is a strong degrader of the environmental pollutant, polychlorinated biphenyls (PCBs). Induction of its degradation enzymes requires an inducing substrate and is conducted by a couple of two-component transcriptional regulators, BphS1T1 and BphS2T2. Mechanism of transcriptional regulation of BphS1T1 and BphS2T2 were examined to develop a strain whose PCB-degradation enzymes are induced by PCBs themselves. Phosphorylation of BphT (BphT1/T2) in the presence of the inducing substrate was indicated. A novel 24-bp consensus sequence was shared among the degradation enzyme gene operon promoters and had necessary and sufficient function for transcriptional induction by BphST, suggesting that the 24-bp sequence serves the binding site for the transcriptional complex including BphT.