以微生物的代谢调控为研究方向，围绕信号转导、转录、翻译后修饰和代谢流分析等方面对微生物次级代谢的调控网络进行解析和重构研究。项目重点研究放线菌对外界氮源及碳氮比变化的感应，针对放线菌氮代谢调控因子GlnR，研究其上游的信号来源，信号感受分子，信号转导途径，以及GlnR蛋白自身的翻译后修饰和其调控功能的关系；进一步揭示GlnR协同调控初级代谢和次级代谢的分子机制。同时，还将研究除GlnR之外的新型信号转导通路及其分子调控网络，探究包括双组份系统在内的调控因子协同调控碳氮代谢以及次级代谢的分子机制。利用代谢流动态分析平台，系统地研究在不同氮源条件下，微生物体内代谢途径/代谢流量的变化；在此基础上，找出关键的中间代谢物和效应分子，并进而揭示其在整个代谢调控网络中的作用以及碳氮代谢调控的分子机制。在现有平台的基础上，进一步发展合成生物学使能技术，完善DNA拼接的标准、大片段DNA操作平台和代谢流动态分析平台。利用模式天蓝色链霉菌和模式大肠杆菌发展合成生物学底盘细胞，并在此基础上重构微生物代谢途径和研究研究其调控模式。

Following the direction of regulation of microbial metabolisms, the aim of the project is to reconstruct and delineate the regulatory network of microbial secondary metabolisms, i.e. through researching into the fields of signal transduction, transcriptional, post-translational modifications and metabolic flux analysis. Specifically, the project focuses on the responses of actinomycetes on the changes of external nitrogen sources and the ratio of carbon/nitrogen concentrations. Based on the previous studies of GlnR, the central regulator for nitrogen metabolisms in actinomycetes, the project is to understand the upstream signals for nitrogen limitation, the signal receptor proteins, the signal transduction pathways, as well as the relationships between the post-translational modification of GlnR and its regulatory functions. In addition, the project tries to reveal the in-depth molecular mechanisms for GlnR-mediated coordinate regulation of the primary metabolisms and secondary metabolisms. Besides of GlnR, the project will also study new regulatory networks for signal transduction, including the two-component systems that coordinately regulate the secondary metabolisms and the primary carbon and nitrogen metabolisms. The project will use the metabolic flux analysis platform to study the dynamic changes of intracellular metabolic pathways/metabolic fluxes under different extracellular nitrogen conditions, and on that basis, the team will try to identify key intermediate metabolites and effector molecules, thus revealing its entire role in coordinate regulation of secondary metabolisms and primary carbon and nitrogen metabolisms. Furthermore, the enabling technology of synthetic biology will be further developed, including improving the standard and the methods for DNA assembly as well as the platform for dynamic analysis of the metabolic fluxes. With the use of model Streptomyces coelicolor and model Escherichia coli, the project is to develop synthetic biology chassis to reconstruct the metabolic pathways and study the molecular mechanisms for their regulation.

微生物代谢生理及其调控的核心科学问题，是微生物为了适应环境变化和细胞生长发育所采取的特定代谢模式以及在转录、翻译及翻译后修饰等水平的控制机理。在本项目的资助下，群体成员整合各自研究优势及技术特色, 在合成生物学使能技术创新及系统生物学检测平台建设上实现突破；在基因组和功能基因组信息基础上，深入解析放线菌、梭菌和蓝细菌的多个代谢途径及调控网络,协作完成从原核微生物到酵母的底盘细胞改造以及高效细胞工厂构建，推动了微生物细胞生物生理学研究，并实现了多种重要代谢产物的高效合成。群体特别重视系统合成生物学技术创新与基础技术平台的建设。六年来，共发展了至少13种DNA拼接及微生物基因组编辑相关的使能技术，为相关研究的深入、底盘细胞构建和代谢途径的改造提供支撑，并在一定程度上推动了合成生物学领域的发展。建立的基因组、代谢组、代谢流量组检测与分析平台以及代谢调控网络解析的生物信息学平台在群体研究中发挥了重要作用，支撑了对以"硝酸盐效应"为主要代表的微生物初级和次级代谢的调控机理及两者协同调控的网络途径解析。采用系统合成生物学研究策略，群体研究证明，硝酸盐通过影响初级代谢以增加前体供给的同时，还从转录水平上提高利福霉素等次级代谢产物的合成能力，最终提高产量，据此提出"硝酸盐效应"的分子机制模型。群体研究了氮代谢、氮/碳代谢、渗透压代谢和次级代谢等途径的调控，解析了以GlnR、CcpA、NrrA等为代表的核心调控蛋白的代谢调控网络。综合使能技术和代谢途径解析的优势，群体开发了迄今为止基因组最小的大肠杆菌、删除了大部分次级代谢途径的天蓝色链霉菌和染色体全整合的酿酒酵母等模式微生物的底盘细胞。这些底盘细胞的成功开发，为群体深入研究微生物细胞生物学科学问题，提升微生物细胞工厂的模块化设计构建、高效检测及与新型代谢通路的精准适配打下基础。