来自热带利什曼原虫的腺嘌呤磷酸核糖转移酶的晶体结构：对APRT催化机制的潜在影响
Crystal structure of adenine phosphoribosyltransferase from Leishmania tarentolae: potential implications for APRT catalytic mechanism.
作者信息
Silva M, Silva C H T P, Iulek J, Oliva G, Thiemann O H
机构信息
Laboratory of Protein Crystallography and Structural Biology, Physics Institute of São Carlos, University of São Paulo-USP, Av. Trabalhador Sãocarlense 400, PO Box 369, 13566-590, São Carlos, SP, Brazil.
出版信息
Biochim Biophys Acta. 2004 Jan 14;1696(1):31-9. doi: 10.1016/j.bbapap.2003.09.003.
The three-dimensional structure of Leishmania tarentolae adenine phosphoribosyltransferase (APRT) in complex with adenosine-5-monophosphate (AMP) and a phosphate ion has been solved. Refinement against X-ray diffraction data extending to 2.2-A resolution led to a final crystallographic R factor of 18.3%. Structural comparisons amongst this APRT enzyme and other 'type I' PRTases whose structures have been determined reveal several important features of the PRTases catalytic mechanism. Based on structural superpositions and molecular interaction potential calculations, it was possible to suggest that the PRPP is the first substrate to bind, while the AMP is the last product to leave the active site, in accordance to recent kinetic studies performed with the Leishmania donovani APRT.
已解析出与5'-磷酸腺苷（AMP）和磷酸离子复合的塔兰托拉利什曼原虫腺嘌呤磷酸核糖转移酶（APRT）的三维结构。针对分辨率达2.2埃的X射线衍射数据进行精修，最终得到的晶体学R因子为18.3%。对该APRT酶与其他结构已确定的“Ⅰ型”磷酸核糖转移酶进行结构比较，揭示了磷酸核糖转移酶催化机制的几个重要特征。基于结构叠加和分子相互作用势能计算，根据最近对杜氏利什曼原虫APRT进行的动力学研究，可以推测磷酸核糖焦磷酸（PRPP）是第一个结合的底物，而AMP是最后一个离开活性位点的产物。
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