一种新的芳烃双加氧酶基因的克隆和功能研究

Cloning and functional study of a novel aromatic-ring-hydroxylating dioxygenase gene

芳烃双加氧酶是多环芳烃在细菌中降解的起始关键酶。本研究通过基因组步移法从地杆菌(Terrabactersp.)中克隆出一种新的双加氧酶基因。采用pET17b载体表达该基因,在共表达电子传递链蛋白的条件下检测获得双加氧酶活性。通过高效液相色谱和气相色谱-质谱分析发现该基因产物可以催化菲、芘和荧蒽生成相应的顺式双羟基产物,表明该基因为一种新型高分子多环芳烃降解基因。

The aromatic-ring-hydroxylating dioxygenase is a key enzyme that initiates the biodcgradation of polycyclic aromatic hydrocarbons in bacteria. In the present study, a novel dioxygcnase sequence was cloned from Terrabacter sp. FLO using a gcnomc walking method. The dioxygcnase was cloned into pET17 and actively expressed in E.coli BL21 （DE3） in co-expression with electron transfer chain proteins. The recombinant dioxygcnasc was found to transform phcnanthrcnc, fluorenc, pyrenc and fluoranthcnc into the cis-dihydrodiol mctabolitcs.