RebG- and RebM-catalyzed indolocarbazole diversification
RebG- and RebM-catalyzed indolocarbazole diversification
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DOI：
10.1002/cbic.200500504
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发表时间：
2006-05-01
期刊：
影响因子：
3.2
通讯作者：
Thorson, Jon S.
中科院分区：
文献类型：
--
作者：
Zhang, Changsheng;Albermann, Christoph;Thorson, Jon S.
诺卡霉素和星形孢菌素代表了两大类具有抗肿瘤特性的吲哚并咔唑糖苷天然产物。基于先前的序列注释和体内研究，rebG编码瑞贝霉素N-葡糖基转移酶，rebM编码必需的4 '-O-甲基转移酶。在本研究中，建立了一个有效的体内生物转化系统的RebG在两个变铅青链霉菌和大肠杆菌。生物转化实验显示RebG使一组吲哚并咔唑替代物葡糖基化，其产物可以通过体外RebM催化的4 '-O-甲基化进一步修饰。RebG和RebM均显示底物混杂，并且还提供了在不对称底物存在下RebG区域选择性的显著锁定的证据。在所产生的吲哚并咔唑类似物的情况下，细胞毒性测定也突出了4 '-O-甲基化对其生物活性的重要性。
Rebeccamycin and staurosporine represent two broad classes of indolocarbazole glycoside natural products with antitumor properties. Based upon previous sequence annotation and in vivo studies, rebG encodes for the rebeccomycin N-glucosyltransferase, and rebM for the requisite 4'-O-methyltransferase. In the current study, an efficient in vivo biotransformation system for RebG was established in both Streptomyces lividans and Escherichia coli. Bioconversion experiments revealed RebG to glucosylate a set of indolocarbazole surrogates, the products of which could be further modified by in vitro RebM-catolyzed 4'-O-methylotion. Both RebG and RebM displayed substrate promiscuity, and evidence for a remarkable lock of RebG regioselectivity in the presence of asymmetric substrates is also provided. In the context of the created indolocarbozole analogues, cytotoxicity assays also highlight the importance of 4'-O-methylation for their biological activity.