Bound volatile general anesthetics alter both local protein dynamics and global protein stability.
Bound volatile general anesthetics alter both local protein dynamics and global protein stability.
复制标题
结合的挥发性全身麻醉剂会改变局部蛋白质动力学和整体蛋白质稳定性。
DOI：
10.1097/00000542-199901000-00030
复制
发表时间：
1999
期刊：
影响因子：
8.8
通讯作者：
Tanner,JW
中科院分区：
文献类型：
--
作者：
Johansson,JS;Zou,H;Tanner,JW
研究背景近年来的研究表明，氟烷和异氟烷等挥发性全身麻醉药可与靶蛋白上的离散位点结合。在牛血清白蛋白的情况下，氟烷和氯仿结合的位点已被确定为位于IB和IIA亚结构域。这一结构信息提供了一个基础，更详细的研究到潜在的机制麻醉action.MethodsThe氟烷和异氟烷和nonimmobilizer 1，2-二氯六氟环丁烷的吲哚环的流动性的白蛋白的色氨酸残基的影响进行了研究，使用荧光各向异性的测量。肌红蛋白用作阴性对照。此外，绑定麻醉剂对全球蛋白质稳定性的影响，确定通过热变性实验，使用近紫外圆二色spectroscopy.ResultsThe荧光各向异性测量表明，氟烷和异氟烷降低吲哚环的流动性，在浓度依赖性的方式。异氟烷和氟烷的计算解离常数分别为1.6+/-0.4和1.3+/-0.3 mM。相比之下，这两种药物未能增加肌红蛋白中色氨酸残基的荧光各向异性，与缺乏结合相容。非固定剂1，2-二氯六氟环丁烷对白蛋白的荧光各向异性没有影响。麻醉剂的结合稳定了白蛋白的天然折叠形式以防止热变性。热变性数据的分析产生的解离常数值为0.98+/-0.10 mM的异氟烷和1.0+/-0.1 mM的halothane.ConclusionsAttenuation的局部侧链动力学和稳定的折叠蛋白质构象可能代表挥发性全身麻醉剂的作用的基本模式。由于蛋白质活性是至关重要的依赖于固有的灵活性，麻醉诱导的某些蛋白质构象的稳定性可以解释这些重要的临床药物如何改变蛋白质功能。
BackgroundRecent studies have demonstrated that volatile general anesthetic agents such as halothane and isoflurane may bind to discrete sites on protein targets. In the case of bovine serum albumin, the sites of halothane and chloroform binding have been identified as being located in the IB and IIA subdomains. This structural information provides a foundation for more detailed studies into the potential mechanisms of anesthetic action.MethodsThe effect of halothane and isoflurane and the nonimmobilizer 1, 2-dichlorohexafluorocyclobutane on the mobility of the indole ring in the tryptophan residues of albumin was investigated using measurements of fluorescence anisotropy. Myoglobin served as a negative control. In addition, the effect of bound anesthetic agents on global protein stability was determined by thermal denaturation experiments using near-ultraviolet circular dichroism spectroscopy.ResultsThe fluorescence anisotropy measurements showed that halothane and isoflurane decreased the mobility of the indole rings in a concentration-dependent manner. The calculated dissociation constants were 1.6+/-0.4 and 1.3+/-0.3 mM for isoflurane and halothane, respectively. In contrast, both agents failed to increase the fluorescence anisotropy of the tryptophan residues in myoglobin, compatible with lack of binding. The nonimmobilizer 1, 2-dichlorohexafluorocyclobutane caused no change in the fluorescence anisotropy of albumin. Binding of the anesthetic agents stabilized the native folded form of albumin to thermal denaturation. Analysis of the thermal denaturation data yielded dissociation constant values of 0.98+/-0.10 mM for isoflurane and 1.0+/-0.1 mM for halothane.ConclusionsAttenuation of local side-chain dynamics and stabilization of folded protein conformations may represent fundamental modes of action of volatile general anesthetic agents. Because protein activity is crucially dependent on inherent flexibility, anesthetic-induced stabilization of certain protein conformations may explain how these important clinical agents change protein function.