Vibrational spectroscopic investigation of the ligand binding domain of kainate receptors.
Vibrational spectroscopic investigation of the ligand binding domain of kainate receptors.
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红藻氨酸受体配体结合域的振动光谱研究。
DOI：
10.1002/pro.174
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发表时间：
2009
期刊：
影响因子：
--
通讯作者：
Jayaraman,Vasanthi
中科院分区：
文献类型：
--
作者：
Du,Mei;Rambhadran,Anu;Jayaraman,Vasanthi
傅里叶变换红外光谱已用于探测GluR 6亚基（谷氨酸受体红藻氨酸亚型的一个亚基）的配体结合结构域中的激动剂-蛋白质相互作用。为了研究在一系列活化过程中相互作用的变化，使用野生型、N690 S和T661 E突变进行了研究。这些研究表明，通过研究非二硫键结合的Cys 432的环境来探测激动剂的α-胺基上的相互作用强度，其作用是一种开关，在较低活化时相互作用较弱，在较高活化时相互作用较强。然而，激动剂的α-羧酸相互作用在广泛的激活范围内没有显著差异，如在激动剂饱和浓度下由受体介导的最大电流所测量的。先前对AMPA受体的研究显示α-胺相互作用对活化的相似依赖性，表明α-胺相互作用在介导受体活化中的作用对于两种受体亚型相似;然而，在AMPA受体的情况下，在α-胺和α-羧酸相互作用之间观察到拔河类型的变化，而在红藻氨酸受体中未观察到。这两种相互作用的解耦可能是由于在红藻氨酸受体中观察到的较大裂缝，这使得激动剂的α-胺和α-羧酸基团的相互作用更加灵活。
Fourier transform infrared spectroscopy has been used to probe the agonist‐protein interactions in the ligand binding domain of the GluR6 subunit, one subunit of the kainate subtype of glutamate receptors. In order to study the changes in the interactions over a range of activations the investigations were performed using the wild type, N690S, and T661E mutations. These studies show that the strength of the interactions at the α‐amine group of the agonist, as probed by studying the environment of the nondisulphide bonded Cys 432, acts as a switch with weaker interactions at lower activations and stronger interactions at higher activations. The α‐carboxylate interactions of the agonist, however, are not significantly different over the wide range of activations, as measured by the maximum currents mediated by the receptors at saturating concentrations of agonists. Previous investigations of AMPA receptors show a similar dependence of the α‐amine interactions on activation indicating that the roles of the α‐amine interactions in mediating receptor activation are similar for both subtypes of receptors; however, in the case of the AMPA receptors a tug of war type of change was observed between the α‐amine and α‐carboxylate interactions and this is not observed in kainate receptors. This decoupling of the two interactions could arise due to the larger cleft observed in kainate receptors, which allows for a more flexible interaction for the α‐amine and α‐carboxylate groups of the agonists.