Forneris Clarissa C, Ozturk Seyma, Gibson Marcus I, Sorensen Erik J, Seyedsayamdost Mohammad R
Departments of Chemistry and ‡Molecular Biology, Princeton University , Princeton, New Jersey 08544, United States.
ACS Chem Biol. 2017 Sep 15;12(9):2248-2253. doi: 10.1021/acschembio.7b00456. Epub 2017 Aug 2.
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.
对糖肽类抗生素生物合成的研究为自然界构建结构紧张分子所采用的策略提供了许多见解。这类抗生素的首个成员万古霉素的一个关键结构特征是一组通过未知机制引入的三个芳香族交联结构。此前的报告已鉴定出参与此过程的三种细胞色素P450酶，并证明了负责安装首个芳香族交联结构的OxyB的酶活性。然而，其余两种P450酶的活性尚未得到重现。在此，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、经OxyB交联的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。结合先前的结果，这些数据表明氯化作用发生在OxyB催化的交联形成之后但在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酶促合成具有重要意义。
