Key Laboratory of Marine Drugs, Ministry of Education of China, School of Medicine and Pharmacy, Ocean University of China, Qingdao, China.
Laboratory for Marine Drugs and Bioproducts, Qingdao National Laboratory for Marine Science and Technology, Qingdao, China.
Appl Environ Microbiol. 2021 Jun 11;87(13):e0029421. doi: 10.1128/AEM.00294-21.
Exploring unknown glycosyltransferases (GTs) is important for compound structural glycodiversification during the search for drug candidates. Piericidin glycosides have been reported to have potent bioactivities; however, the GT responsible for piericidin glucosylation remains unknown. Herein, BmmGT1, a macrolide GT with broad substrate selectivity and isolated from Bacillus methylotrophicus B-9987, was found to be able to glucosylate piericidin A1 . Next, the codon-optimized GT gene , which was designed based on BmmGT1, was heterologously expressed in the piericidin producer Streptomyces youssoufiensis OUC6819. Piericidin glycosides thus significantly accumulated, leading to the identification of four new glucopiericidins (compounds 3, 4, 6, and 7). Furthermore, using BmmGT1 as the probe, was identified in the genome of OUC6819 and demonstrated to be associated with piericidin glucosylation; the overexpression of this gene led to the identification of another new piericidin glycoside, acetylglucosamine-piericidin (compound 8). Compounds 4, 7, and 8 displayed cytotoxic selectivity toward A549, A375, HCT-116, and HT-29 solid cancer cell lines compared to the THP-1 lymphoma cell line. Moreover, database mining of GT1507 homologs revealed their wide distribution in bacteria, mainly in those belonging to the high-GC Gram-positive and clades, thus representing the potential for identification of novel tool enzymes for compound glycodiversification. Numerous bioactive natural products are appended with sugar moieties and are often critical for their bioactivities. Glycosyltransferases (GTs) are powerful tools for the glycodiversification of natural products. Although piericidin glycosides display potent bioactivities, the GT involved in glucosylation is unclear. In this study, five new piericidin glycosides (compounds 3, 4, 6, 7, and 8) were generated following the overexpression of GT-coding genes in a piericidin producer. Three of them (compounds 4, 7, and 8) displayed cytotoxic selectivity. Notably, was demonstrated to be related to piericidin glucosylation . Furthermore, mining of GT1507 homologs from the GenBank database revealed their wide distribution across numerous bacteria. Our findings would greatly facilitate the exploration of GTs to glycodiversify small molecules in the search for drug candidates.
探索未知的糖基转移酶（GTs）对于寻找候选药物时化合物结构的糖基多样化非常重要。已经报道了 Piericidin 糖苷具有很强的生物活性；然而，负责 Piericidin 糖基化的 GT 仍然未知。本文中，从 Bacillus methylotrophicus B-9987 中分离得到的具有广泛底物选择性的大环 GT BmmGT1 能够对 Piericidin A1 进行葡萄糖基化。接下来，基于 BmmGT1 设计的经过密码子优化的 GT 基因在 Piericidin 产生菌 Streptomyces youssoufiensis OUC6819 中异源表达。Piericidin 糖苷因此显著积累，导致了四个新的葡萄糖基化 Piericidin（化合物 3、4、6 和 7）的鉴定。此外，使用 BmmGT1 作为探针，在 OUC6819 的基因组中鉴定到了，并证明与 Piericidin 的葡萄糖基化有关；该基因的过表达导致了另一个新的 Piericidin 糖苷，乙酰葡萄糖胺-Piericidin（化合物 8）的鉴定。与 THP-1 淋巴瘤细胞系相比，化合物 4、7 和 8 对 A549、A375、HCT-116 和 HT-29 实体癌细胞系表现出细胞毒性选择性。此外，GT1507 同源物的数据库挖掘表明它们在细菌中广泛分布，主要存在于高 GC 革兰氏阳性和 枝菌目中，因此代表了鉴定用于化合物糖基多样化的新型工具酶的潜力。许多生物活性天然产物都缀有糖基，并且通常对其生物活性至关重要。糖基转移酶（GTs）是天然产物糖基多样化的有力工具。尽管 Piericidin 糖苷显示出很强的生物活性，但参与糖基化的 GT 尚不清楚。在这项研究中，通过在 Piericidin 产生菌中过表达 GT 编码基因，生成了五个新的 Piericidin 糖苷（化合物 3、4、6、7 和 8）。其中三个（化合物 4、7 和 8）表现出细胞毒性选择性。值得注意的是，被证明与 Piericidin 的葡萄糖基化有关。此外，从 GenBank 数据库中挖掘 GT1507 同源物表明它们在许多细菌中广泛分布。我们的发现将极大地促进 GTs 的探索，以在寻找候选药物时使小分子糖基多样化。
