Characterizing Amosamine Biosynthesis in Amicetin Reveals AmiG as a Reversible Retaining Glycosyltransferase
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- 作者：Ruidong Chen ; Haibo Zhang ; Gaiyun Zhang ; Sumei Li ; Guangtao Zhang ; Yiguang Zhu ; Jinsong Liu ; Changsheng Zhang
- 刊名：The Journal of the American Chemical Society
- 出版年：2013
- 出版时间：August 21, 2013
- 年：2013
- 卷：135
- 期：33
- 页码：12152-12155
- 全文大小：267K
- 年卷期：v.135,no.33(August 21, 2013)
- ISSN：1520-5126
文摘
The antibacterial and antiviral agent amicetin is a disaccharide nucleoside antibiotic featuring a unique 伪-(1鈫?)-glycoside bond between amosamine and amicetose, characteristic of a retaining glycosylation. In this study, two key steps for amosamine biosynthesis were investigated: the N-methyltransferase AmiH was demonstrated to be requisite for the dimethylation in amosamine, and the glycosyltransferase AmiG was shown to be necessary for amosaminylation. Biochemical and kinetic characterization of AmiG revealed for the first time the catalytic reversibility of a retaining glycosyltransferase involved in secondary metabolite biosynthesis. AmiG displayed substrate flexibility by utilizing five additional sugar nucleotides as surrogate donors. AmiG was also amenable to sugar and aglycon exchange reactions. This study indicates that AmiG is a potential catalyst for diversifying nucleoside antibiotics and paves the way for mechanistic studies of a natural-product retaining glycosyltransferase.