曼陀罗霉素的生物合成探索及一株链霉菌的化学成分研究

	曼陀罗霉素的生物合成探索及一株链霉菌的化学成分研究; Exploring the Biosynthesis of Daturamycins and Chemical Constituents of a Streptomyces sp.
	任金秋
导师	黄胜雄
摘要	The terphenyl natural products show diverse biological activities including antibacteria, anti-tumor, anti-oxidation, DNA topoisomerase inhibition and immunosuppressants. They are mainly isolated from higher fungi and microorganisms. However, terphenyl natural products from Streptomyces stains are relatively few. In the previous study, our team identified four new terphenyl products (daturamycins A-D) from the fermentation extract of S. sp. KIB-H1544 isolated from rhizospheric soil of Datura stramonium L. Since the biosynthesis of unique five-membered carbon ring in these novel p-terphenyl compounds has not been reported, a biosynthetic study was carried out to determine its origin. As a whole, this thesis was divided into three chapters. Chapter one described the exploration of the biosynthesis of p-terphenyl compounds, daturamycins A-D, which were isolated from S. sp. KIB-H1544. Chapter two were about the Streptomyces strains isolation from rhizosphere soil of four plants and the structural identification and biological activity study of the secondary metabolites from S. sp. KIB-H1714, which was isolated from the rhizosphere soil of plant Phyllanthus urinaria L. In the last chapter, the research progress of p-terphenyls including their structures, bioactivities, and biosynthesis was summarized. In chapter one, the exploration of daturamycins A-D biosynthesis was presented. It’s the chemical structure and related literature reports indicated that its biosynthesis involved in condensation of two benzene pyruvic acid molecules. This reaction was mediated by a nonribosomal peptide synthetase (NRPS) with three domains. As a result, genes datA-E were identified as the biosynthetic genes of daturamycins A-D based on gene disruption experiments. DatA is a benzoquinone synthase, whose function is determined by in vitro enzyme reaction to catalyze the condensation of two-molecule α-phenylpyruvate to form the precursor polyporic acid. According to literature reports, we speculated that two redox enzymes, DatB and DatE, could reduce a carbonyl group and double bond of the intermediate polyporic acid to a hydroxyl group and a single bond, respectively. Under the action of DatC, a molecule of water was removed to form a benzene ring with three hydroxyl groups. The secondary metabolites and biological activity were described in chapter two. 115 actinomycete strains were isolated from four soil samples. Four soil-derived strains (Streptomyces sps. KIB-H1471, KIB-H1424, KIB-H1414, KIB-H1714) were selected for biological activity study of the secondary metabolites based on high performance liquid chromatography (HPLC) profile. By a combined use of silica gel column chromatography, thin layer chromatography, and HPLC, three compounds 1-3 were isolated from the fermentation extract of S. sp. KIB-H1714. Their structures were identified by nuclear magnetic resonance, mass spectrum, and X-ray crystal diffraction. Compounds 1 and 2 were identified as novel quinolizine
	2020-05
文献类型	学位论文
条目标识符	http://ir.kib.ac.cn/handle/151853/74169
专题	昆明植物所硕博研究生毕业学位论文
推荐引用方式 GB/T 7714	任金秋. 曼陀罗霉素的生物合成探索及一株链霉菌的化学成分研究, Exploring the Biosynthesis of Daturamycins and Chemical Constituents of a Streptomyces sp.[D],2020.

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