METABOLIC SPECIFICITY OF METHYLTHIOCOFORMYCIN FOR MALARIAL ADENOSINE DEAMINASE

甲硫基辅霉素对疟疾腺苷脱氨酶的代谢特异性

• 批准号: 8169275
• 负责人: STEVEN G ALMO
• 金额: $ 0.17万
• 依托单位: CORNELL UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2010
• 资助国家: 美国
• 起止时间: 2010-04-01 至 2011-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8169275
• 关键词: Adenine Nucleotides; Adenosine; Affinity; Binding; Binding Sites; Catalytic Domain; Coformycin; Complex; Computer Retrieval of Information on Scientific Projects Database; Enzymes; Erythrocytes; Funding; Grant; Human; Hydrogen Bonding; Hydroxyl Radical; Hypoxanthines; Institution; Kinetics; Metabolic; Mutagenesis; Pathway interactions; Pentostatin; Plasmodium; Plasmodium falciparum; Plasmodium gallinaceum; Plasmodium vivax; Purine Nucleotides; Purines; Reporting; Research; Research Personnel; Resources; Source; Specificity; Structure; Substrate Specificity; United States National Institutes of Health; Water; adenosine deaminase; analog; base; purine

This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. Plasmodium falciparum is a purine auxotroph requiring hypoxanthine as a key metabolic precursor. Erythrocyte adenine nucleotides are the source of the purine precursors, making adenosine deaminase (ADA) a key enzyme in the pathway of hypoxanthine formation in Plasmodium falciparum. Methylthioadenosine (MTA) is one of purine nucleotide substrates for most malarial ADAs, but not for human ADA. The catalytic site specificity of malarial ADAs permits methylthiocoformycin (MT-coformycin) to act as a Plasmodium-specific transition state analogue with low affinity for human ADA [Tyler, P. C., Taylor, E. A., Frohlich, R. G. G., and Schramm, V. L. (2007) J. Am. Chem. Soc. 129, 6872-6879]. The structural basis for MTA and MT-coformycin specificity in malarial ADAs is the subject of speculation. In this study, we report the crystal structure of ADA from Plasmodium vivax (PvADA) in a complex with MT-coformycin that reveals an unprecedented binding geometry for 5'-methylthioribosyl groups in the malarial ADAs. Compared to malarial ADA complexes with adenosine or deoxycoformycin, 5'-methylthioribosyl groups are rotated 130 degrees . A hydrogen bonding network between Asp172 and the 3'-hydroxyl of MT-coformycin is essential for recognition of the 5'-methylthioribosyl group. Water occupies the 5'-hydroxyl binding site when MT-coformycin is bound. Mutagenesis of Asp172 destroys the substrate specificity for MTA and MT-coformycin. Kinetic, mutagenic, and structural analyses of PvADA and kinetic analysis of five other Plasmodium ADAs establish the unique structural basis for its specificity for MTA and MT-coformycin. Plasmodium gallinaceum ADA does not use MTA as a substrate, is not inhibited by MT-coformycin, and is missing Asp172.

该副本是利用众多研究子项目之一 由NIH/NCRR资助的中心赠款提供的资源。子弹和 调查员（PI）可能已经从其他NIH来源获得了主要资金， 因此可以在其他清晰的条目中代表。列出的机构是 对于中心，这不一定是调查员的机构。 恶性疟原虫是一种嘌呤的合子营养，需要低黄嘌呤作为关键代谢前体。红细胞腺嘌呤核苷酸是嘌呤前体的来源，使腺苷脱氨酶（ADA）成为恶性疟原虫中低黄嘌呤形成途径的关键酶。对于大多数疟疾ADA而言，甲基噻吩并腺苷（MTA）是嘌呤核苷酸底物之一，但对于人ADA而言不是。疟疾ADAS的催化位点特异性允许甲基噻唑霉素（MT-甲霉素）充当疟原虫特异性过渡状态模拟，对人ADA的亲和力低，[Tyler，P. C.，Tyler，P. C.，Taylor，E。A.，E。A.化学Soc。 129，6872-6879]。疟疾ADA中MTA和MT-甲霉素特异性的结构基础是投机的主题。在这项研究中，我们报告了与MT-合子素的复合物中ADA的晶体结构，该结构揭示了疟疾ADAS中5'-麦甲基丁基基团的前所未有的结合几何形状。与腺苷或葡萄糖霉素的疟疾ADA复合物相比，旋转130度。 MT-甲霉素的ASP172和3'-羟基之间的氢键网络对于识别5'-甲基硫糖基团的识别至关重要。当MT-合霉素结合时，水占据了5'-羟基结合位点。 ASP172的诱变破坏了MTA和MT-甲霉素的底物特异性。 PVADA的动力学，诱变和结构分析和其他五个疟原虫ADA的动力学分析为其对MTA和MT-菌霉素的特异性建立了独特的结构基础。 Gallinaceum ADA疟原虫不使用MTA作为底物，不受MT-合霉素的抑制，并且缺失了ASP172。