Linear Aglycones Are the Substrates for Glycosyltransferase DesVII in Methymycin Biosynthesis: Analysis and Implications

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• 作者：Chai-Lin Kao ; Svetlana A. Borisova ; Hak Joong Kim ; and Hung-wen Liu
• 刊名：Journal of the American Chemical Society
• 出版年：2006
• 出版时间：May 3, 2006
• 年：2006
• 卷：128
• 期：17
• 页码：5606 - 5607
• 全文大小：70K
• 年卷期：v.128,no.17(May 3, 2006)
• ISSN：1520-5126

文摘

The two essential structural components of macrolide antibiotics are the polyketide aglycone and the appended sugars. The aglycone formation is catalyzed by polyketide synthase (PKS), and glycosylation is catalyzed by an appropriate glycosyltransferase. Although it has been shown that glycosylation occurs after the cyclic aglycone is released from PKS, it is not known whether the acyl carrier protein (ACP)-bound linear polyketide chain can also be processed by the corresponding glycosyltransferase. To explore this possibility, the aglycone, 10-deoxymethynolide, which is the precursor of methymycin and neomethymycin, was chemically synthesized in the linear form as a N-acetylcysteamine (NAC) thioester. Subsequent incubation with TDP-D-desosamine in the presence of the dedicated glycosyltransferase, DesVII, and activator, DesVIII, produces a more polar product whose high-resolution mass is consistent with the anticipated glycosylated product. This study demonstrated for the first time that a macrolide glycosyltransferase can also recognize and process the linear precursor of its macrolactone substrate with a reduced but measurable activity.