Triatoma infestans apyrases belong to the 5′-Nucleotidase family
Triatoma infestans apyrases belong to the 5′-Nucleotidase family
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DOI：
10.1074/jbc.m401681200
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发表时间：
2004-05-07
影响因子：
4.8
通讯作者：
Teixeira, ARL
中科院分区：
文献类型：
--
作者：
Faudry, E;Lozzi, SP;Teixeira, ARL
APYrase是存在于多种生物体中的核苷三磷酸-二磷酸水解酶(EC 3.6.1.5)。在食血昆虫唾液中发现的apyrase活性与防止ADP在吸血过程中诱导宿主的血小板聚集有关。采用寡聚(DT)-纤维素亲和层析和凝胶过滤层析的方法纯化了致病三角毛虫唾液中的apyrase活性。分离得到的部分包括5个N-糖基化多肽，其表观分子质量分别为88、82、79、68和67 kDa。分离的apyrase混合物完全抑制了人血小板的聚集。用ATP底物类似物5‘-对氟磺酰苯甲酰腺苷标记表明，这5种植物具有功能apyrase的ATP结合特性。此外，串联质谱肽序列分析表明，这5个物种与埃及伊蚊的apyrase和其他物种的5‘-核苷酸酶有相似的序列。克隆了该79 kDa酶的全长cDNA，测序结果表明该酶编码5‘-核苷酸酶家族的apyrase。致病毛滴虫唾液apyrase多样性的基因倍增除了逃避宿主免疫反应外，还可能是在昆虫进化为嗜血性的过程中放大酶表达的重要机制，从而增强这种查加斯病的三原子载体获取食物的能力。
Apyrases are nucleoside triphosphate-diphosphohydrolases (EC 3.6.1.5) present in a variety of organisms. The apyrase activity found in the saliva of hematophagous insects is correlated with the prevention of ADP-induced platelet aggregation of the host during blood sucking. Purification of apyrase activity from the saliva of the triatomine bug Triatoma infestans was achieved by affinity chromatography on oligo(dT)-cellulose and gel filtration chromatography. The isolated fraction includes five N-glycosylated polypeptides of 88, 82, 79, 68 and 67 kDa apparent molecular masses. The isolated apyrase mixture completely inhibited aggregation of human blood platelets. Labeling with the ATP substrate analogue 5'-p-fluorosulfonylbenzoyladenosine showed that the five species have ATP-binding characteristic of functional apyrases. Furthermore, tandem mass spectroscopy peptide sequencing showed that the five species share sequence similarities with the apyrase from Aedes aegypti and with 5'-nucleotidases from other species. The complete cDNA of the 79-kDa enzyme was cloned, and its sequence confirmed that it encodes for an apyrase belonging to the 5'-nucleotidase family. The gene multiplication leading to the unusual salivary apyrase diversity in T. infestans could represent an important mechanism amplifying the enzyme expression during the insect evolution to hematophagy, in addition to an escape from the host immune response, thus enhancing acquisition of a meal by this triatomine vector of Chagas' disease.