Mascaretti O A, Chang C J, Hook D, Otsuka H, Kreutzer E F, Floss H G
Biochemistry. 1981 Feb 17;20(4):919-24. doi: 10.1021/bi00507a042.
Feeding experiments with 13C-labeled precursors followed by 13C NMR analysis of the antibiotic and its aglycon have established a polyketide mode of biosynthesis for chlorothricin, a metabolite of Streptomyces antibioticus. The acyl moiety is a substituted 6-methylsalicylic acid derived from four acetate units and a methyl group of methionine. The aglycon is comprised of ten acetate and two propionate units, leaving three carbon atoms, C-22, -23, and -24, unaccounted for. The two 2-deoxy-D-rhamnose moieties are derived from glucose with retention of the hydrogens at C-1, C-2, and C-6 and loss of H-3 and H-5. The hydrogen at C-4 of glucose is transferred intramolecularly to C-6 of the hexose, replacing the hydroxyl group at C-6 in an inversion mode, a result which implicates the thymidine 5'-diphosphate-glucose oxidoreductase reaction in this transformation.
用13C标记的前体进行喂养实验，随后对抗生素及其苷元进行13C NMR分析，确定了由抗生链霉菌产生的代谢产物氯霉素的聚酮生物合成模式。酰基部分是一种取代的6-甲基水杨酸，由四个乙酸单位和甲硫氨酸的一个甲基衍生而来。苷元由十个乙酸单位和两个丙酸单位组成，剩下三个碳原子，即C-22、-23和-24未说明来源。两个2-脱氧-D-鼠李糖部分由葡萄糖衍生而来，C-1、C-2和C-6上的氢得以保留，而H-3和H-5则丢失。葡萄糖C-4上的氢在分子内转移至己糖的C-6，以反转模式取代C-6上的羟基，这一结果表明胸苷5'-二磷酸葡萄糖氧化还原酶反应参与了这一转化过程。
