Studies on the biosynthesis of glycopeptide antibiotics have provided many insights into the strategies that Nature employs to build architecturally strained molecules. A key structural feature of vancomycin, the founding member of this class, is a set of three aromatic cross-links that are introduced via yet unknown mechanisms. Previous reports have identified three cytochrome P450 enzymes involved in this process and demonstrated enzymatic activity for OxyB, which installs the first aromatic cross-link. However, the activities of the remaining two P450 enzymes have not been recapitulated. Herein, we show that OxyA generates the second bis-aryl ether bond in vancomycin and that it exhibits strict substrate specificity toward the chlorinated, OxyB-cross-linked product. No OxyA product is detected with the unchlorinated substrate. Together with previous results, these data suggest that chlorination occurs after OxyB- but before OxyA-catalyzed cross-link formation. Our results have important implications for the chemo-enzymatic synthesis of vancomycin and its analogs.

中文翻译：

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OxyA酶活性的体外重建澄清了万古霉素生物合成的后期步骤。

糖肽抗生素生物合成的研究为自然界用来构建结构紧张分子的策略提供了许多见解。该类别的创始成员万古霉素的关键结构特征是通过以下方式引入的三个芳香族交联的集合尚不清楚的机制。先前的报告已鉴定出此过程中涉及的三种细胞色素P450酶，并证明了对OxyB的酶促活性，OxyB安装了第一个芳族交联键。但是，其余两种P450酶的活性尚未概括。在本文中，我们表明OxyA在万古霉素中生成第二个双芳基醚键，并且它对氯化的OxyB交联产物表现出严格的底物特异性。未氯化的底物未检测到OxyA产物。与以前的结果一起，这些数据表明氯化发生在OxyB-之后但在OxyA催化的交联形成之前。我们的结果对万古霉素及其类似物的化学合成具有重要意义。