Three-dimensional structure of M-tuberculosis dihydrofolate reductase reveals opportunities for the design of novel tuberculosis drugs
Three-dimensional structure of M-tuberculosis dihydrofolate reductase reveals opportunities for the design of novel tuberculosis drugs
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DOI：
10.1006/jmbi.1999.3328
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发表时间：
2000-01-14
影响因子：
5.6
通讯作者：
Hol, WGJ
中科院分区：
文献类型：
--
作者：
Li, RB;Sirawaraporn, R;Hol, WGJ
二氢叶酸还原酶(DHFR)催化NADPH依赖的二氢叶酸还原为四氢叶酸，是合成胸苷、嘌呤和几种氨基酸所必需的。抑制该酶的活性会导致DNA合成停滞和细胞死亡。该酶已被广泛研究为治疗细菌、原虫和真菌感染以及肿瘤和自身免疫性疾病的药物靶点。在这里，我们报告了结核分枝杆菌二氢叶酸还原酶的晶体结构，结核分枝杆菌是一种人类病原体，每年导致数百万人死亡。测定了结核分枝杆菌DHFR与NADP和不同缓蚀剂的三元络合物以及与NADP的二元络合物的晶体结构，其分辨率为1.7~2.0埃。这三种DHFR抑制剂是抗癌药物甲氨蝶呤、抗菌剂甲氧苄啶和BR-WR99210，BR-WR99210是抗疟疾药物WR99210的类似物。这些复合体与人二氢叶酸还原酶的结构比较表明，尽管只有26%的序列相同，但总的蛋白质折叠相似，但NADP和抑制剂的环境在宿主和病原体的酶之间存在有趣的差异。具体地说，NADP N6附近的残基A1a101和Leu102在结核分枝杆菌中明显比在人类酶中更疏水性。另一个显著的差异出现在甲氨蝶呤的N1和N8原子附近，也是甲氧苄氨嘧啶的N1原子附近，以及BR-WR99210的N1和两个甲基附近。甘油分子结合在结核分枝杆菌DHFR：MTX复合体的一个口袋里，而这个口袋基本上充满了人类酶中的疏水侧链。这些来自病原体和宿主的酶之间的差异为设计新的结核分枝杆菌DHFR选择性抑制剂提供了机会。(C)2000年学术出版社。
Dihydrofolate reductase (DHFR) catalyzes the NADPH-dependent reduction of dihydrofolate to tetrahydrofolate and is essential for the synthesis of thymidylate, purines and several amino acids. Inhibition of the enzyme's activity leads to arrest of DNA synthesis and cell death. The enzyme has been studied extensively as a drug target for bacterial, protozoal and fungal infections, and also for neoplastic and autoimmune diseases. Here, we report the crystal structure of dihydrofolate reductase from Mycobacterium tuberculosis, a human pathogen responsible for the death of millions of human beings per year. Three crystal structures of ternary complexes of M. tuberculosis DHFR with NADP and different inhibitors have been determined, as well as the binary complex with NADP, with resolutions ranging from 1.7 to 2.0 Angstrom. The three DHFR inhibitors are the anticancer drug methotrexate, the antimicrobial trimethoprim and Br-WR99210, an analogue of the antimalarial agent WR99210. Structural comparison of these complexes with human dihydrofolate reductase indicates that the overall protein folds are similar, despite only 26 % sequence identity, but that the environments of both NADP and of the inhibitors contain interesting differences between the enzymes from host and pathogen. Specifically, residues A1a101 and Leu102 near the N6 of NADP are distinctly more hydrophobic in the M. tuberculosis than in the human enzyme. Another striking difference occurs in a region near atoms N1 and N8 of methotrexate, which is also near atom N1 of trimethoprim, and near the N1 and two methyl groups of Br-WR99210. A glycerol molecule binds here in a pocket of the M, tuberculosis DHFR:MTX complex, while this pocket is essentially filled With hydrophobic side-chains in the human enzyme. These differences between the enzymes from pathogen and host provide opportunities for designing new selective inhibitors of M. tuberculosis DHFR. (C) 2000 Academic Press.