Identification of critical structural determinants responsible for octopamine binding to the α-adrenergic-like Bombyx mori octopamine receptor
Identification of critical structural determinants responsible for octopamine binding to the α-adrenergic-like Bombyx mori octopamine receptor
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DOI：
10.1021/bi602593t
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发表时间：
2007-05-22
期刊：
影响因子：
2.9
通讯作者：
Ozoe, Yoshihisa
中科院分区：
文献类型：
--
作者：
Huang, Jia;Hamasaki, Tomohiro;Ozoe, Yoshihisa
章鱼胺（Octopamine， OA）是一种广泛分布于昆虫神经系统的生物胺。OA作为一种神经递质、神经调节剂和神经激素调节和/或调节昆虫的各种行为模式。OA受体（OARs）属于G蛋白偶联受体（gpcr）家族之一。OA与OARs的结合与特定G蛋白的激活相结合，从而诱导细胞内第二信使如cAMP和/或钙的释放。我们以前报道过从家蚕中分离到一个OAR （BmOAR1）。在本研究中，我们构建了5个突变的bmoar1，在假定的结合缝中有一个点突变，并在HEK-293细胞中表达。发现S202A突变受体与野生型受体一样保留了对OA的cAMP反应，但在其他四个突变体（D103A, S198A， Y412F和S198A/S202A）中，这种功能受损。此外，使用[H-3]OA的竞争结合测定和钙动员测定的结果与cAMP测定的结果大致一致。综上所述，结果表明D103和S198通过静电或氢键相互作用参与了BmOAR1与OA的结合和激活，而S202似乎没有参与这一过程。Y412似乎参与了BmOAR1的一种活性形式。这些发现将有助于设计新的害虫防治化学品。
Octopamine (OA) is a biogenic amine with a widespread distribution in the insect nervous system. OA modulates and/or regulates various behavioral patterns of insects as a neurotransmitter, neuromodulator, and neurohormone. OA receptors (OARs) belong to one of the families of G protein-coupled receptors (GPCRs). The binding of OA to OARs is coupled to the activation of the specific G proteins, which induces the release of intracellular second messengers such as cAMP and/or calcium. We previously reported the isolation of an OAR (BmOAR1) from Bombyx mori. In the study presented here, five mutated BmOAR1s were constructed with a point mutation in the putative binding crevice and expressed in HEK-293 cells. The S202A mutant receptor was found to retain the cAMP response to OA as does the wild-type receptor, but such function was impaired in the other four mutants (D103A, S198A, Y412F, and S198A/S202A). Furthermore, competition binding assays using [H-3]OA and calcium mobilization assays gave results that were approximately consistent with those of the cAMP assays. Taken together, the results indicate that D103 and S198 are involved in the binding and activation of BmOAR1 with OA through electrostatic or hydrogen bond interactions, but S202 does not appear to participate in this process. Y412 seems to be involved in one of the active forms of BmOAR1. These findings should prove helpful in designing new pest control chemicals.