BIOLOGICALLY ACTIVE MICROBIAL METABOLITES

这项建议中概述的研究旨在阐明 一些抗生素的生物合成。化合物和有待解决的问题 所研究的包括形成吡咯硝酸酯的酶学和 二氢苯丙氨酸，环己烷环的形成 阿舒卡霉素、安沙三烯、萘霉素和/或mC7N单位的形成 一种是利福霉素，另一种是阿苏霉素和曼纽霉素， 聚酮在溶血脂素和大二内酯中的组装方式 阿维菌素，以及还原霉素的生物合成 吩嗪类抗生素、esmeraldins和ashenamcins，以及经修饰的 多肽抗生素诺西肽和硫链菌素。结果在意料之中 回答抗生素生物合成中的基本问题并奠定基础 复合抗生素生物结构修饰的基础工作 基于生物合成信息。拟采用的方法包括(A) 放射性(~(14)C，~3H)标记前体的饲喂实验 和/或稳定的(13C、15N、18O、2H)同位素和广泛使用的傅立叶- 用于产物分析的变换核磁共振波谱，(B)势的合成 途径中间体及其在全细胞和无细胞条件下的评价 实验，(C)进行某些实验的酶的分离 转化和(D)立体特异性标记的合成和用途 底物，以探索立体化学和机制的一些 生物合成反应。

The research outlined in this proposal is aimed at elucidating the mode of biosynthesis of a number of antibiotics. Compounds and problems to be studied include the enzymology of formation of pyrrolnitrin and dihydrophenylalanine, the formation of cyclohexane rings in ansatrienin and asukamycin, the formation of mC7N units in ansatrienin, naphthomycin and/or rifamycin on the one hand, and in asukamycin and manumycin on the other, the mode of polyketide assembly in lysolipin and in the macrodiolide aplasmomycin, as well as the biosynthesis of reductiomycin, the novel phenazine antibiotics, the esmeraldins and saphenamycins, and the modified peptide antibiotics nosiheptide and thiostrepton. The results are expected to answer fundamental questions in antibiotic biosynthesis and lay the ground work for biological structure modification of complex antibiotics based on biosynthetic information. The methods to be used include (a) feeding experiments with precursors labeled with radioactive (14C, 3H) and/or stable (13C, 15N, 18O, 2H) isotopes and extensive use of Fourier- transform NMR spectroscopy for product analysis, (b) synthesis of potential pathway intermediates and their evaluation in whole cell or cell-free experiments, (c) isolation of enzymes carrying out some of these transformations and (d) synthesis and use of stereospecifically labeled substrates to probe the stereochemistry and mechanism of some of the biosynthetic reactions.