细胞色素P450酶广泛分布于自然界各种生命体内,具有底物结构类型丰富和催化反应类型多样的两大特点,被誉为自然界中的“万能催化剂”.P450酶可在温和条件下催化复杂有机化合物中惰性C—H键的区位或立体专一性高的氧化官能化,广泛参与天然产物的生物合成、异源物质的降解等生命活动,且在医药、化工、食品、农业等诸多领域具有广阔的应用价值和潜力.本文综述了参与深海来源天然产物生物合成的P450酶的底物结构特征及催化功能的研究现状,并对深海来源P450酶的发掘、功能鉴定及应用进行了展望.
Background: Cytochrome P450 enzymes (P450s), recognized as the most versatile enzymes in nature, broadly exist in all kinds of living organisms and hold the greatest diversity in substrate structures and catalytic reaction types. P450s are capable of catalyzing the regio- and stereo-specific oxidative functionalization of non-activated C-H bonds in complex organic compounds under mild conditions and are widely involved in natural product biosynthesis, xenobiotic degradation, and other life activities. Accordingly, P450s show valuable application and potential in medicine, chemical industry, food, agriculture, and other related fields. In this review, we summarize the substrate structural types and functions of P450s involved in the biosynthesis of deep-sea derived natural product and provide prospects for the discovery, functional research and application of deep-sea P450s.
Progress: Recently, hundreds of natural products have been isolated from deep-sea microorganisms, including terpenoids, polyketides, non-ribosomal peptides and alkaloids, which show diverse biological activities and significant application potential in pharmaceutical industry. The unique biosynthetic mechanism of active natural products from the deep sea has also attracted the attention of chemists, biochemists and pharmaceutists. Through bioinformatic analysis, P450s are predicted to play essential roles in deep-sea microbial natural product biosynthesis. With the efforts of several research groups, a number of deep-sea microbial P450s involved in the polyketide, non-ribosomal peptide and the hybrid polyketide/non-ribosomal peptide biosynthetic pathways have been identified from the biosynthetic gene cluster by in vivo or in vitro studies. The reaction types of these novel P450s include hydroxylation, epoxidation, ketonization, nitration, ether bridge formation, C-N bond formation and others. These findings reveal the versatile role of P450s in the skeleton construction, structural modification and bioactivity improvement of deep-sea active natural products, and show the vast applicable potential of P450s in the production of medicine and fine chemicals. Meanwhile, with the development of deep-sea exploration and DNA sequencing technologies, the quantity of deep-sea microbial P450 genes deposited in databases has sharply increased, demonstrating the great development and research value in constructing the deep-sea P450s library.
Perspective: Nowadays, the discovery of deep-sea microbial natural products and the research on the structural biology and catalytic mechanism of deep-sea P450s are still very limited. Moreover, the research on deep-sea P450s mainly focuses on the physiological and biochemical functions of actinomycotic P450s involved in natural product biosynthesis, while the study of catalytic mechanism and structural biology exploration is lacking. In comparison, the function research on P450s from deep-sea fungi, algae and animals, especially the orphan P450s, is rare.
From a long-term perspective, the research of the functional characterization and potential application of deep-sea P450s would require interdisciplinary knowledge and technologies: 1) the design and development of advanced deep-sea equipment to promote the sustainable development and acquisition of deep-sea biological resources; 2) the acquisition of unculturable deep-sea microorganisms and breakthroughs in in situ culture technologies; 3) the application of various molecular biology and genetic technologies, including epigenetic modification, whole-genome sequencing, silent gene activation and heterologous expression, to achieve functional characterization of deep-sea derived microbial natural product biosynthetic gene clusters containing P450 genes; 4) the collection of P450 sequences in the deep-sea environment and the construction of relevant database by metagenomics sequencing and bioinformatic analysis; 5) the acquisition of high activity and selectivity P450 mutants using deep-sea derived microbial P450s as the templates to meet the demands of industries via structure biology and direction evolution approaches. We believe the multidimensional research of deep-sea derived microbial P450s will greatly advance the functional understanding of P450s involved in the natural product biosynthesis, expand the P450 toolbox, and promote the development of synthetic biology and related industrial fields.
