The function and three-dimensional structure of a thromboxane A2/cysteinyl leukotriene-binding protein from the saliva of a mosquito vector of the malaria parasite.
The function and three-dimensional structure of a thromboxane A2/cysteinyl leukotriene-binding protein from the saliva of a mosquito vector of the malaria parasite.
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DOI：
10.1371/journal.pbio.1000547
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发表时间：
2010-11-30
期刊：
影响因子：
9.8
通讯作者：
Andersen JF
中科院分区：
文献类型：
--
作者：
Alvarenga PH;Francischetti IM;Calvo E;Sá-Nunes A;Ribeiro JM;Andersen JF
一种来自传播疟疾的蚊子的唾液蛋白利用一个单一的结构域与血栓烷A2和半胱氨酰白三烯结合，防止它所喂养的宿主的血液凝固和炎症。蚊子唾液的高表达D 7蛋白家族先前已显示通过结合宿主生物胺和半胱氨酰白三烯（CysLTs）而充当抗炎介质。在这项研究中，我们表明，AnSt-D 7 L1，这组从斯氏按蚊的两个结构域的成员，保留CysLT结合功能中看到的同源AeD 7从埃及伊蚊，但失去了结合生物胺的能力。与任何先前表征的D 7家族成员不同，AnSt-D 7 L1获得了以高亲和力结合血栓烷A2（TXA 2）及其类似物的重要功能。当给予组织制剂时，AnSt-D 7 L1消除白三烯C4（LTC 4）诱导的豚鼠回肠收缩和TXA 2类似物U46619引起的大鼠主动脉收缩。蛋白质也抑制血小板聚集诱导的胶原蛋白和U46619时，给药搅拌血小板。AnSt-D 7 L1的晶体结构包含两个OBP样结构域，具有与AeD 7相似的结构。在AnSt-D 7 L1中，C-末端结构域的结合口袋相对于AeD 7已经重排，使得蛋白质不能结合生物胺。配体复合物的结构表明，CysLTs和TXA 2类似物都结合在N-末端结构域的相同疏水口袋中。TXA 2类似物U46619通过ω-5羟基与Tyr 52的酚羟基的氢键相互作用而稳定。LTC 4和占据一个非常相似的位置，以LTE 4在先前确定的结构，其复杂的AeD 7。到目前为止，还不知道重新排列的C-末端结构域已经获得了什么新功能（如果有的话）。本文介绍，据我们所知，第一个结构表征的蛋白质从蚊子唾液，抑制胶原介导的血小板活化。在进食时，雌蚊必须抑制宿主的血液凝固和炎症反应。为了做到这一点，昆虫产生唾液蛋白，中和参与凝血和炎症的关键宿主分子。在这里，我们描述了一种唾液蛋白AnSt-D 7 L1，清除thomboxane A2和半胱氨酰白三烯，两种物质参与血管收缩，血小板聚集和炎症反应的昆虫叮咬。我们在细菌中产生了这种蛋白质，并表明它与这两种分子紧密结合，抑制了它们参与的过程。然后，我们确定了其结构，使用X-射线晶体学和表明，有一个单一的结合位点在一个域的蛋白质，容纳血栓烷A2和半胱氨酰白三烯，这个网站是负责清除作用的蛋白质。这些研究揭示了与具有潜在药理学重要性的关键分子结合所需的蛋白质的结构特征，并增加了我们对蚊子吸血过程的理解，这对疟疾寄生虫的传播至关重要。
A salivary protein from a malaria-transmitting mosquito uses a single domain to bind to thromboxane A2 and cysteinyl leukotrienes and prevent blood clotting and inflammation in the host on which it feeds. The highly expressed D7 protein family of mosquito saliva has previously been shown to act as an anti-inflammatory mediator by binding host biogenic amines and cysteinyl leukotrienes (CysLTs). In this study we demonstrate that AnSt-D7L1, a two-domain member of this group from Anopheles stephensi, retains the CysLT binding function seen in the homolog AeD7 from Aedes aegypti but has lost the ability to bind biogenic amines. Unlike any previously characterized members of the D7 family, AnSt-D7L1 has acquired the important function of binding thromboxane A2 (TXA2) and its analogs with high affinity. When administered to tissue preparations, AnSt-D7L1 abrogated Leukotriene C4 (LTC4)-induced contraction of guinea pig ileum and contraction of rat aorta by the TXA2 analog U46619. The protein also inhibited platelet aggregation induced by both collagen and U46619 when administered to stirred platelets. The crystal structure of AnSt-D7L1 contains two OBP-like domains and has a structure similar to AeD7. In AnSt-D7L1, the binding pocket of the C-terminal domain has been rearranged relative to AeD7, making the protein unable to bind biogenic amines. Structures of the ligand complexes show that CysLTs and TXA2 analogs both bind in the same hydrophobic pocket of the N-terminal domain. The TXA2 analog U46619 is stabilized by hydrogen bonding interactions of the ω-5 hydroxyl group with the phenolic hydroxyl group of Tyr 52. LTC4 and occupies a very similar position to LTE4 in the previously determined structure of its complex with AeD7. As yet, it is not known what, if any, new function has been acquired by the rearranged C-terminal domain. This article presents, to our knowledge, the first structural characterization of a protein from mosquito saliva that inhibits collagen mediated platelet activation. When feeding, a female mosquito must inhibit the blood clotting and inflammatory responses of the host. To do this, the insect produces salivary proteins that neutralize key host molecules participating in clotting and inflammation. Here, we describe a salivary protein AnSt-D7L1 that scavenges both thomboxane A2 and cysteinyl leukotrienes, two substances involved in blood vessel constriction, platelet aggregation, and inflammatory responses to an insect bite. We produced this protein in bacteria and showed that it tightly binds both these molecules, inhibiting the processes in which they are involved. We then determined its structure using X-ray crystallography and showed that there is a single binding site in one domain of the protein, accommodating both thromboxane A2 and cysteinyl leukotrienes, and that this site is responsible for the scavenging effect of the protein. These studies reveal the structural features of proteins needed to bind to key molecules of potential pharmacological importance and add to our understanding of the process of mosquito blood feeding, which is essential for transmission of the malaria parasite.
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影响因子：
6.5
作者：
Andoh, Tsugunobu;Nishikawa, Yumi;Kuraishi, Yasushi
通讯作者：
Kuraishi, Yasushi
影响因子：
2.8
作者：
Francischetti, IMB;Saliou, B;Bon, C
通讯作者：
Bon, C
DOI：
10.1107/s0907444904019158
发表时间：
2004-12-01
影响因子：
2.2
作者：
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通讯作者：
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影响因子：
6.5
作者：
BISGAARD, H
通讯作者：
BISGAARD, H
影响因子：
2.9
作者：
BISGAARD, H;KRISTENSEN, J;SONDERGAARD, J
通讯作者：
SONDERGAARD, J