Structures of Leishmania major pteridine reductase complexes reveal the active site features important for ligand binding and to guide inhibitor design
Structures of Leishmania major pteridine reductase complexes reveal the active site features important for ligand binding and to guide inhibitor design
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DOI：
10.1016/j.jmb.2005.06.076
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发表时间：
2005-09-09
影响因子：
5.6
通讯作者：
Hunter, WN
中科院分区：
文献类型：
--
作者：
Schüttelkopf, AW;Hardy, LW;Hunter, WN
蝶啶还原酶（PTR 1）是一种存在于寄生性锥虫原虫中的NADPH依赖性短链还原酶。这种酶参与蝶呤的抢救，并代表了针对这些寄生虫引起的感染开发改进疗法的目标。本文报道了硕大利什曼原虫PTR 1的一系列晶体学分析。与辅因子NADPH的二元复合物和与辅因子和生物蝶呤、5，6-二氢生物蝶呤和5，6，7，8-四氢生物蝶呤的三元复合物中的酶的结构揭示PTR 1不经历任何主要的构象变化来完成底物的结合和加工，并证实这些分子在适合于两种不同还原的催化中心以单一方向结合。三元复合物与辅因子和CB 3717和甲氧苄啶（TOP），有效的抑制剂胸苷酸合成酶和二氢叶酸还原酶，分别进行了表征。CB 3717的结构显示喹唑啉部分以类似的方式与蝶呤底物/产物结合，并主导与酶的相互作用。在与TOP的复合物中，对三甲氧基苯基取代基实施的空间限制防止2，4-二氨基嘧啶部分采用在二氢叶酸还原酶中观察到的蝶呤结合模式，并解释了一系列嘧啶衍生物的抑制特性。这些复杂结构提供的分子细节确定了重要的相互作用，以帮助基于结构的开发具有潜在治疗价值的新型酶抑制剂。(c)2005爱思唯尔有限公司保留所有权利。
Pteridine reductase (PTR1) is an NADPH-dependent short-chain reductase found in parasitic trypanosomatid protozoans. The enzyme participates in the salvage of pterins and represents a target for the development of improved therapies for infections caused by these parasites. A series of crystallographic analyses of Leishmania major PTR1 are reported. Structures of the enzyme in a binary complex with the cofactor NADPH, and ternary complexes with cofactor and biopterin, 5,6-dihydrobiopterin, and 5,6,7,8-tetrahydrobiopterin reveal that PTR1 does not undergo any major conformational changes to accomplish binding and processing of substrates, and confirm that these molecules bind in a single orientation at the catalytic center suitable for two distinct reductions. Ternary complexes with cofactor and CB3717 and trimethoprim (TOP), potent inhibitors of thymidylate synthase and dihydrofolate reductase, respectively, have been characterized. The structure with CB3717 reveals that the quinazoline moiety binds in similar fashion to the pterin substrates/ products and dominates interactions with the enzyme. In the complex with TOP, steric restrictions enforced on the trimethoxyphenyl substituent prevent the 2,4-diaminopyrimidine moiety from adopting the pterin mode of binding observed in dihydrofolate reductase, and explain the inhibition properties of a range of pyrimidine derivates. The molecular detail provided by these complex structures identifies the important interactions necessary to assist the structure-based development of novel enzyme inhibitors of potential therapeutic value. (c) 2005 Elsevier Ltd. All rights reserved.