细菌Rieske非血红素铁环羟化酶在多环芳烃降解中的研究进展

Advances in bacterial Rieske non-heme iron ring-hydroxylating dioxygenases that initiate polycyclic aromatic hydrocarbons degradation

多环芳烃是一种常见的持久性有机污染物,因具有致癌、致突变等毒性而被广泛关注。其微生物降解过程通常由羟化起始,随后脱氢、开环、一步步去除支链,最终进入三羧酸循环。Rieske非血红素铁环羟化酶(Rieske-type non-heme iron aromatic ring-hydroxylating oxygenases,RHOs,又称aromatic ring-hydroxylating dioxygenases)或细胞色素P450氧化酶负责将羟基加成到多环芳烃环上,将疏水性的多环芳烃转化为亲水性的衍生物,这一过程是多环芳烃降解转化的起始步骤,也是关键步骤和限速步骤之一。文中主要介绍RHOs的分布、底物特异性、底物识别机制以及研究RHOs与多环芳烃的一些技术和方法等,并对RHOs在环境修复技术中的潜在应用进行了展望。

Polycyclic aromatic hydrocarbons(PAHs)are a class of persistent organic pollutants,which have received widespread attentions due to their carcinogenic and mutagenic toxicity.The microbial degradation of PAHs are usually started from the hydroxylation,followed by dehydrogenation,ring cleavage and step-by-step removal of branched chains,and finally mineralized by the tricarboxylic acid cycle.Rieske type non-heme iron aromatic ring-hydroxylating dioxygenases(RHOs)or cytochrome P450 oxidases are responsible for the conversion of hydrophobic PAHs into hydrophilic derivatives by the ring hydroxylation.The ring hydroxylation is the first step of PAHs degradation and also one of the rate-limiting steps.Here,we review the distribution,substrate specificity,and substrate recognition mechanisms of RHOs,along with some techniques and methods used for the research of RHOs and PAHs.