Linear Aglycones Are the Substrates for Glycosyltransferase DesVII in Methymycin Biosynthesis: Analysis and Implications
作者:Chai-Lin Kao、Svetlana A. Borisova、Hak Joong Kim、Hung-wen Liu
DOI:10.1021/ja058433v
日期:2006.5.1
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
大环内酯类抗生素的两个基本结构成分是聚酮苷元和附加糖。苷元的形成由聚酮合酶 (PKS) 催化,糖基化由适当的糖基转移酶催化。虽然已经表明糖基化发生在环状苷元从 PKS 释放后,但尚不清楚与酰基载体蛋白 (ACP) 结合的线性聚酮链是否也可以被相应的糖基转移酶处理。为了探索这种可能性,以线性形式化学合成了作为 N-乙酰半胱胺 (NAC) 硫酯的糖苷配基 10-脱氧甲炔内酯,它是甲霉素和新甲霉素的前体。随后在专用糖基转移酶 DesVII 和激活剂 DesVIII 存在下与 TDP-d-desosamine 孵育,产生极性更强的产物,其高分辨率质量与预期的糖基化产物一致。该研究首次证明大环内酯糖基转移酶也可以识别和加工其大环内酯底物的线性前体,但活性降低但可测量。