Yang Yunyun, Ko Tzu-Ping, Chen Chun-Chi, Huang Guozhong, Zheng Yingying, Liu Weidong, Wang Iren, Ho Meng-Ru, Hsu Shang-Te Danny, O'Dowd Bing, Huff Hannah C, Huang Chun-Hsiang, Docampo Roberto, Oldfield Eric, Guo Rey-Ting
College of Biotechnology, Tianjin University of Science and Technology , Tianjin 300457, China.
Industrial Enzymes National Engineering Laboratory, Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences , Tianjin, 300308, China.
ACS Chem Biol. 2016 May 20;11(5):1362-71. doi: 10.1021/acschembio.5b00724. Epub 2016 Mar 4.
Trypanosomatid parasites are the causative agents of many neglected tropical diseases, including the leishmaniases, Chagas disease, and human African trypanosomiasis. They exploit unusual vacuolar soluble pyrophosphatases (VSPs), absent in humans, for cell growth and virulence and, as such, are drug targets. Here, we report the crystal structures of VSP1s from Trypanosoma cruzi and T. brucei, together with that of the T. cruzi protein bound to a bisphosphonate inhibitor. Both VSP1s form a hybrid structure containing an (N-terminal) EF-hand domain fused to a (C-terminal) pyrophosphatase domain. The two domains are connected via an extended loop of about 17 residues. Crystallographic analysis and size exclusion chromatography indicate that the VSP1s form tetramers containing head-to-tail dimers. Phosphate and diphosphate ligands bind in the PPase substrate-binding pocket and interact with several conserved residues, and a bisphosphonate inhibitor (BPH-1260) binds to the same site. On the basis of Cytoscape and other bioinformatics analyses, it is apparent that similar folds will be found in most if not all trypanosomatid VSP1s, including those found in insects (Angomonas deanei, Strigomonas culicis), plant pathogens (Phytomonas spp.), and Leishmania spp. Overall, the results are of general interest since they open the way to structure-based drug design for many of the neglected tropical diseases.
锥虫寄生虫是许多被忽视的热带疾病的病原体，包括利什曼病、恰加斯病和人类非洲锥虫病。它们利用人类所没有的特殊液泡可溶性焦磷酸酶（VSPs）来实现细胞生长和致病，因此这些酶是药物靶点。在此，我们报告了来自克氏锥虫和布氏锥虫的VSP1的晶体结构，以及与双膦酸盐抑制剂结合的克氏锥虫蛋白的晶体结构。两种VSP1都形成一种混合结构，包含一个（N端）EF手结构域与一个（C端）焦磷酸酶结构域融合。这两个结构域通过一个约17个残基的延伸环相连。晶体学分析和尺寸排阻色谱表明，VSP1形成包含头对头二聚体的四聚体。磷酸盐和二磷酸盐配体结合在PPase底物结合口袋中，并与几个保守残基相互作用，一种双膦酸盐抑制剂（BPH - 1260）也结合在同一位置。基于Cytoscape和其他生物信息学分析，很明显，在大多数（如果不是全部）锥虫寄生虫的VSP1中会发现相似的折叠结构，包括在昆虫（德氏按蚊、库蚊斯特里戈莫纳斯）、植物病原体（植原体属）和利什曼原虫属中发现的那些。总体而言，这些结果具有普遍意义，因为它们为许多被忽视的热带疾病的基于结构的药物设计开辟了道路。
