A tight coupling between β₂Y97 and β₂F200 of the GABA(A) receptor mediates GABA binding.
A tight coupling between β₂Y97 and β₂F200 of the GABA(A) receptor mediates GABA binding.
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DOI：
10.1111/j.1471-4159.2011.07409.x
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发表时间：
2011-10
影响因子：
4.7
通讯作者：
Wagner DA
中科院分区：
文献类型：
--
作者：
Tran PN;Laha KT;Wagner DA
GABAA受体是一种低聚五聚体氯离子通道，通过内源性配体GABA与细胞外亚单位间界面结合而引起的构象变化而激活。虽然α/β界面上的数十个氨基酸残基与配体结合有关，但介导配体结合和受体激活的结构元件尚未完全描述。在这里，使用双突变循环分析来测试几种精氨酸(α1R67、α1R120、α1R132和β2R207)与两个芳香族残基(β2Y97和β2F200)之间可能的相互作用，这些残基存在于配体结合口袋中，已知会影响GABA亲和力。结果表明，α1R67和α1R120均未与这两种芳香族化合物发生官能化偶联，而α1R132与两种芳香族残基之间存在中等程度的偶联。β2R207与β2Y97和β2F200之间存在显著的功能偶联。此外，我们还发现了两个芳香族化合物β2Y97和β2F200之间存在更强的偶联作用，并首次为β2Y97和β2F200参与GABA结合提供了直接证据。由于这些残基紧密相连，并且其中任何一个的突变对GABA结合和受体动力学都有类似的严重影响，我们认为它们形成了一个可能直接协调GABA的单一功能单位。
The GABAA receptor is an oligopentameric chloride channel that is activated via conformation changes induced upon the binding of the endogenous ligand, GABA, to the extracellular inter-subunit interfaces. While dozens of amino acid residues at the α/β interface have been implicated in ligand binding, the structural elements that mediate ligand binding and receptor activation are not yet fully described. Here, double-mutant cycle analysis was employed to test for possible interactions between several arginines (α1R67, α1R120, α1R132, and β2R207) and two aromatic residues (β2Y97 and β2F200) that are present in the ligand-binding pocket and are known to influence GABA affinity. Our results show that neither α1R67 nor α1R120 is functionally coupled to either of the aromatics, while a moderate coupling exists between α1R132 and both aromatic residues. Significant functional coupling between β2R207 and both β2Y97 and β2F200 was found. Furthermore, we identified an even stronger coupling between the two aromatics, β2Y97 and β2F200, and for the first time provided direct evidence for the involvement of β2Y97 and β2F200 in GABA binding. As these residues are tightly linked, and mutation of either has similar, severe effects on GABA binding and receptor kinetics, we believe they form a single functional unit that may directly coordinate GABA.
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影响因子：
3.6
作者：
Laha, Kurt T.;Wagner, David A.
通讯作者：
Wagner, David A.
影响因子：
2.9
作者：
Crowley, PB;Golovin, A
通讯作者：
Golovin, A
影响因子：
64.8
作者：
Kash, TL;Jenkins, A;Harrison, NL
通讯作者：
Harrison, NL
影响因子：
--
作者：
Lummis, SCR;Beene, DL;Dougherty, DA
通讯作者：
Dougherty, DA
影响因子：
3.9
作者：
Kash, TL;Trudell, JR;Harrison, NL
通讯作者：
Harrison, NL