Dual Carbamoylations on the Polyketide and Glycosyl Moiety by Asm21 Result in Extended Ansamitocin Biosynthesis
Dual Carbamoylations on the Polyketide and Glycosyl Moiety by Asm21 Result in Extended Ansamitocin Biosynthesis
复制标题
Asm21 对聚酮化合物和糖基部分的双氨基甲酰化导致安丝菌素生物合成延长
DOI：
10.1016/j.chembiol.2011.11.007
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发表时间：
2011-12-23
影响因子：
--
通讯作者：
Deng, Zixin
中科院分区：
文献类型：
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作者：
Li, Yan;Zhao, Peiji;Deng, Zixin
氨甲酰化是抗菌肽生物合成中的pks后修饰之一。从抗菌菌素产生菌放线菌属（Actinosynnema pretiosum）中鉴定出一种新的氨甲酰取代n - β - d -葡萄糖基部分C-4羟基的抗菌菌苷。通过生物转化，碳氨酰基转移酶基因asm21被认为负责葡萄糖基部分的碳氨酰基化。从asm21突变体中分离到三个不含主链氨基甲酰的新衍生物，并用核磁共振光谱对其进行了表征。其中，18- o -甲基-19-氯原氨霉素是Asm21对大内酰胺C-7氨基甲酰化的主要产物和首选底物。而Asm21对葡萄糖基部分表现出更高的催化效率。此外，双氨基甲酰化和n -糖基化在体内得到了精确的证实。这项工作代表了在抗菌菌素生物合成过程中对聚酮骨架和糖基部分进行双重作用的o -氨基甲酰转移酶的第一个生化表征。
Carbamoylation is one of the post-PKS modifications in ansamitocin biosynthesis. A novel ansamitocinoside with carbamoyl substitution at the C-4 hydroxyl group of the N-beta-D-glucosyl moiety was identified from the ansamitocin producer, Actinosynnema pretiosum. Through biotransformation, the carbamoyltransferase gene asm21 was suggested to be responsible for the carbamoylation of the glucosyl moiety. Three new derivatives without the backbone carbamoyl group were isolated from an asm21 mutant and characterized by NMR spectroscopy. Among them, 18-O-methyl-19-chloroproansamitocin was the major product and the preferred substrate for macrolactam C-7 carbamoylation by Asm21. However, Asm21 exhibited higher catalytic efficiency toward the glucosyl moiety. Furthermore, the dual carbamoylations and N-glycosylation were precisely demonstrated in vivo. This work represents the first biochemical characterization of an O-carbamoyltransferase performing dual actions on both a polyketide backbone and a glycosyl moiety during ansamitocin biosynthesis.