Molecular Determinants of Potent P2X2 Antagonism Identified by Functional Analysis, Mutagenesis, and Homology Docking
Molecular Determinants of Potent P2X2 Antagonism Identified by Functional Analysis, Mutagenesis, and Homology Docking
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DOI：
10.1124/mol.110.068700
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发表时间：
2011-04-01
影响因子：
3.6
通讯作者：
Hausmann, Ralf
中科院分区：
文献类型：
--
作者：
Wolf, Christian;Rosefort, Christiane;Hausmann, Ralf
P2 X2受体是阳离子通道的ATP门控P2 X家族的成员，并且它们参与交感神经节和中间神经元中的神经传递。在此，我们在一系列139种苏拉明衍生物中鉴定了7，7 '-（羰基双（亚氨基-3，1-亚苯基羰基亚氨基-3，1-（4-甲基亚苯基）羰基亚氨基））双（1-甲氧基-萘-3，6-二磺酸）四氢叶酸盐（NF 770）作为纳摩尔有效的竞争性P2 X2受体拮抗剂。三个结构决定因素有助于NF 770抑制P2 X2受体：1）具有两个对称亚苯基羰基亚氨基的“大脲”结构; 2）在位置7，7 '处连接萘部分;和3）萘部分处两个磺酸基团（3，3'; 6，6 '）和一个甲氧基（1，1'）的特定位置。这种结构-活性关系被解释使用大鼠P2 X2同源模型的基础上的晶体结构的封闭斑马鱼P2 X4受体。苏拉明衍生物对接到模型的ATP结合口袋提供了一个统一的解释所观察到的抑制效力的差异。化学结构的变化，增加苏拉明衍生物的抑制效力，提高了ATP结合口袋内的空间取向，使更强的极性相互作用的功能基团与Gly 72，Glu 167，或Arg 290。Gly 72负责甲氧基靠近Arg 290或Glu 167的取向。结合突变和功能的分析证实，残基Gly 72和Glu 167是重要的ATP结合的Arg 290，ATP结合的作用已在以前的研究中显示。Gly 72和Glu 167作为ATP结合残基的计算机预测强烈支持我们的同源对接的有效性。
P2X2 receptors are members of the ATP-gated P2X family of cation channels, and they participate in neurotransmission in sympathetic ganglia and interneurons. Here, we identified 7,7'-(carbonylbis(imino-3,1-phenylenecarbonylimino-3,1-(4-methylphenylene) carbonylimino))bis(1-methoxy-naphthalene-3,6-disulfonic acid) tetrasodium salt (NF770) as a nanomolar-potent competitive P2X2 receptor antagonist within a series of 139 suramin derivatives. Three structural determinants contributed to the inhibition of P2X2 receptors by NF770: 1) a "large urea" structure with two symmetric phenylenecarbonylimino groups; 2) attachment of the naphthalene moiety in position 7,7'; and 3) the specific position of two sulfonic acid groups (3,3'; 6,6') and of one methoxy group (1,1') at the naphthalene moiety. This structure-activity relationship was interpreted using a rat P2X2 homology model based on the crystal structure of the closed zebrafish P2X4 receptor. Docking of the suramin derivatives into the modeled ATP-binding pocket provides a uniform explanation for the observed differences in inhibitory potencies. Changes in the chemical structure that increase the inhibitory potency of the suramin derivatives improved the spatial orientation within the ATP-binding pocket to allow for stronger polar interactions of functional groups with Gly72, Glu167, or Arg290. Gly72 is responsible for the orientation of the methoxy group close to Arg290 or Glu167. Combined mutational and functional analysis confirmed that residues Gly72 and Glu167 are as important for ATP binding as Arg290, the ATP-binding role of which has been shown in previous studies. The in silico prediction of Gly72 and Glu167 as ATP-binding residues strongly supports the validity of our homology docking.