海洋放线菌Streptomyces koyangensis SCSIO 5802中多烯大环内酯类抗生素candicidin生物合成基因簇的分析鉴定  

Identification of biosynthetic gene cluster of polyene marcrolide antibiotic candicidin from marine-derived Streptomyces koyangensis SCSIO 5802

作　　者：涂佳佳 鞠建华[2] 付少彬 李青连[2] Tu Jiajia;Ju Jianhua;Fu Shaobin;Li Qinglian(Department of Medicinal Chemistry,School of Pharmacy,Zunyi Medical University,Zunyi Guizhou 563099,China;CAS Key Laboratory of Tropical Marine Bio-resources and Ecology,Guangdong Key Laboratory of Tropical Marine Materia Medica,South China Sea Institute of Oceanology,Chinese Academy of Sciences,Guangzhou Guangdong 510301,China)

机构地区：[1]遵义医科大学药学院药物化学教研室,贵州遵义563099 [2]中国科学院南海海洋所中国科学院热带海洋资源与生态重点实验室,广东广州510301

出　　处：《遵义医学院学报》2019年第1期35-44,共10页Journal of Zunyi Medical University

基　　金：国家自然科学基金资助项目(NO:31670087; 21462057)

摘　　要：目的从一株深海放线菌S.koyangensis SCSIO 5802中分析鉴定多烯大环内酯类抗生素candicidin的生物合成基因簇,并推导其生物合成途径。方法①利用PCR-targeting方法对负责abyssomicin类化合物的聚酮合酶abmB1进行同框缺失,并利用HPLC-MS对获得的突变株SCSIO 5802A代谢产物进行分析以鉴定其它新型化合物;②利用生物信息学方法对S.koyangensis SCSIO 5802的全基因组序列进行注释分析,以寻找candicidin的生物合成基因簇;③结合candicidin结构特征、基因簇内生物合成基因的功能以及I型聚酮化合物的生物合成原理,对其生物合成途径进行推导;④利用阿普拉抗性基因片段对candicidin生物合成基因簇中的聚酮合酶基因canD进行替换突变,以确定基因簇的正确性。结果 abmB1基因的同框缺失突变株SCSIO 5802A不生产abyssomicins类化合物,从该突变株中鉴定了一类之前未发现的多烯大环内酯类化合物candicidins;利用生物信息学鉴定了candicidin生物合成基因簇,并对其生物合成途径进行了推导;对聚酮合酶基因canD进行抗性替换突变获得的突变株SCSIO 5802AC不生产candicidins类化合物,确认了该基因簇的正确性。结论本研究将为利用组合生物合成的方法获得candicidin新结构衍生物以及基于基因组信息的新型天然产物挖掘奠定了基础。Objective To identify the biosynthetic gene cluster of polyene antibiotic candicidins from the deep-sea derived S.koyangensis SCSIO 5802,and to propose the putative biosynthetic pathway for candicidins. Methods (1) The type I polyketide synthase (PKS), abmB1 ,which is responsible for assembly of the polyketide backbone of abyssomicins,was inactivated by in-frame deletion to generate the mutant strain SCSIO 5802A.The metabolites of the mutant strain SCSIO 5802A was analyzed by using HPLC-MS.(2) The biosynthetic gene cluster of candicidin was identified by using bioformatic analysis of the genome sequence of S.koyangensis SCSIO 5802.(3) The biosynthetic pathway for candicidins was proposed based on the structure of feature of candicidin,the putative functions of the biosynthetic genes and the general biosynthetic logic for the assembly of type I polyketide antibiotics.(4) The polyketide synthase, canD ,responsible for assembly of the polyketide backbone of candicidins was repaleced by apramycin resistance gene cassette. Results The polyene macrolide antibiotic candicidin was identified from the in-frame deletion mutant strain SCSIO 5802 in which the production of abyssomicins was completely abolished.The biosynthetic gene cluster of candicidins was identified and the biosynthetic pathway for candicidins was proposed based on bioinformatics analysis.And the biosynthetic gene cluster of candicidin was confirmed by gene replacement of the type I PKS, canD . Conclusion The results in this study will pave the way for generation of candicidin derivatives by combinatorial biosynthesis as well as discovery of new natural product via genome mining.

关 键 词：S.koyangensisSCSIO5802 多烯大环内酯 生物合成 基因簇 

分 类 号：R284.1[医药卫生—中药学]