School of Infection and Immunity, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow G12 8TA, UK.
Department of Zoonoses, Faculty of Veterinary Medicine, Sohag University, Sohag 82524, Egypt.
Molecules. 2022 Nov 19;27(22):0. doi: 10.3390/molecules27228045.
Among the scarce validated drug targets against Chagas disease (CD), caused by , the parasite's nucleoside salvage system has recently attracted considerable attention. Although the trypanocidal activity of tubercidin (7-deazapurine) has long been known, the identification of a class of 7-substituted tubercidin analogs with potent in vitro and in vivo activity and much-enhanced selectivity has made nucleoside analogs among the most promising lead compounds against CD. Here, we investigate the recently identified TcrNT2 nucleoside transporter and its potential role in antimetabolite chemotherapy. TcrNT2, expressed in a cell line lacking the NT1 nucleoside transporter locus, displayed very high selectivity and affinity for thymidine with a K of 0.26 ± 0.05 µM. The selectivity was explained by interactions of 2-oxo, 4-oxo, 5-Me, 3'-hydroxy and 5'-hydroxy with the transporter binding pocket, whereas a hydroxy group at the 2' position was deleterious to binding. This made 5-halogenated 2'-deoxyuridine analogues good substrates but 5-F-2'-deoxyuridine displayed disappointing activity against trypomastigotes. By comparing the EC values of tubercidin and its 7-substituted analogues against Cas9, Cas9 and Cas9 it was shown that TcrNT2 can take up tubercidin and, at a minimum, a subset of the analogs.
在针对恰加斯病（CD）的稀缺验证药物靶点中，寄生虫的核苷补救系统最近引起了相当大的关注。尽管 tubercidin（7-脱氮嘌呤）的杀锥虫活性早已为人所知，但一类具有强大体外和体内活性且选择性大大提高的 7-取代 tubercidin 类似物的鉴定使得核苷类似物成为最有前途的 CD 抗代谢化疗先导化合物之一。在这里，我们研究了最近鉴定的 TcrNT2 核苷转运蛋白及其在抗代谢化疗中的潜在作用。在缺乏 NT1 核苷转运蛋白基因座的细胞系中表达的 TcrNT2 对胸苷表现出非常高的选择性和亲和力，K 为 0.26±0.05µM。这种选择性可以通过 2-酮、4-酮、5-Me、3'-羟基和 5'-羟基与转运蛋白结合口袋的相互作用来解释，而 2'位的羟基则对结合不利。这使得 5-卤代 2'-脱氧尿苷类似物成为良好的底物，但 5-F-2'-脱氧尿苷对 Trypomastigotes 的活性令人失望。通过比较 tubercidin 及其 7-取代类似物对 Cas9、Cas9 和 Cas9 的 EC 值，可以表明 TcrNT2 可以摄取 tubercidin 及其至少一部分类似物。
