新资源溶杆菌中活性天然产物的发现与生物合成

The discovery of new anti-infective drugs is a pressing and continual need for human health due to the constant emergence of drug resistant and new pathogens. The neglected or nonpopular classes of microbes has been bringed to light as capable secondary metabolite producers due to the recent massive surge in whole-genome sequencing projects. The underexplored gram-negative lysobacter is one of them, which have been recognized as new resources for new therapeutic agents. Previously, we have isolated HSAFs, the antifungal antibiotics with novel mode of action, from Lysobacter enzymogenes C3, and WAP-8294A2, a cyclic lipodepsipeptide with potent anti-methicillin-resistant Staphylococcus aureus activity and currently in phase I/II clinical trials, from L. enzymogenes OH11. We have also deciphered the biosynthetic mechanisms of HSAF and WAP8294A2, respectively. Notably, full genome sequence analysis of strain OH11 and other reported Lysobacter spp. revealed that these organisms possess more potential secondary metabolic biosynthetic clusters than reported metabolites. In this proposal, we are planning to explore the biosynthetic potential of lysobacter strains by traditional approaches coupled with genomics-inspired strategies to identify new bioactive natural products. We will also carry out the biosynthetic studies on these novel compounds. The knowledge obtained here will be helpful to establish an efficient method that is suitable for the discovery of natural products from lysobacter strains, and set the foundation for other related research. Meanwhile, the outcomes of this project may provide new leads for further drug development.

新抗生素的发现在耐药菌和新型病原菌不断出现的今天显得尤为迫切。随着大量生物基因组信息的获得，人们认识到曾经被忽视的微生物类群同样具有丰富的次级代谢产物合成途径，革兰氏阴性菌溶杆菌即是其中之一。前期，我们从产酶溶杆菌C3和OH11中获得了抗真菌机制独特的HSAF类抗生素和抗耐药菌的环脂肽WAP8294A2，并阐明了其生物合成途径。进一步对前期研究菌株和已公布序列溶杆菌的基因组分析，我们发现其中还蕴含丰富的未知次级代谢产物合成途径。基于此，本项目拟开展前期研究相对较少的溶杆菌次级代谢产物的深度挖掘，利用传统天然产物发现与基因组发掘相结合策略，从溶杆菌中获得新活性天然产物，并开展相关生物合成研究。本项目的完成将有望建立一套适用于溶杆菌天然产物发现与生物合成研究的高效模式，为后续该领域的相关研究提供借鉴；并有望发现具有潜在开发价值的药物先导，为我国具有自主知识产权的新药创制奠定基础。

新活性天然产物是新药研发的重要来源，随着基因组测序的大规模开展，人们发现前期研究较少的微生物类群也具有丰富的次级代谢途径。本项目对新资源革兰氏阴性溶杆菌开展了天然产物发现与生物合成研究。首先，利用基因组测序技术和生物信息学分析筛选出多个次级代谢途径丰富的溶杆菌菌株；随后同时利用传统天然产物研究方法和基因组发掘策略开展了活性成分研究，从抗生素溶杆菌中定向发现了一类选择性抑制MRSA的新型环脂肽WBP-29479A1，具有药用开发潜力。此外，我们系统开展了产酶溶杆菌代谢产生的抗真菌化合物HSAF的多环体系合成机制研究，深入解析了其生物合成途径和结构多样性形成机制，并利用组合生物合成策略合成了具有独特氧化修饰的新HSAF类似物，为后续该类化合物的产量提升、组分简化和结构改造奠定了基础。