Electrostatic interaction between anions bound to site I and the retinal Schiff base of halorhodopsin.
Electrostatic interaction between anions bound to site I and the retinal Schiff base of halorhodopsin.
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结合位点 I 的阴离子与盐视紫红质的视网膜席夫碱之间的静电相互作用。
DOI：
10.1021/bi00362a026
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发表时间：
1986
期刊：
影响因子：
2.9
通讯作者：
Lanyi,JK
中科院分区：
文献类型：
--
作者：
Schobert,B;Lanyi,JK
加州大学生理学和生物物理学系，尔湾，加利福尼亚州 92717 收稿日期：1985 年 11 月 13 日；修订稿于 1986 年 1 月 21 日收到摘要：研究了黑暗中不同阴离子对盐视紫红质视网膜席夫碱去质子化的影响。我们发现大量阴离子会导致希夫碱的 p/sfa 显着增加，这种效应归因于与蛋白质上“位点 I”的结合。与 p 的变化相关的光谱位移的浓度依赖性产生了阴离子的解离常数（以及因此的结合能），其与斯托克斯半径相关。如果后者位于距蛋白质表面几埃的范围内，则该数据符合与位点 I 相关的阴离子和正电荷之间静电相互作用的预测。位点 I 对各种阴离子的特异性可以通过阴离子从水中转移到结合位点时玻恩能量变化的差异来定量解释。阴离子结合时希夫碱去质子化能的变化，AAGdeprot，可以根据无限阴离子浓度下的 ApKa 来计算。没想到的是，
Department of Physiology and Biophysics, University of California, Irvine, California 92717 Received November 13, 1985; Revised Manuscript Received January 21, 1986 abstract: The influence of different anions on the deprotonation of the retinalSchiff base of halorhodopsin in the dark was investigated. We find that a large number of anions cause a significant increase of the p/sfa of the Schiff base, an effect attributed to binding to “site I” on the protein. The concentration de-pendencies of the spectroscopic shifts associated with the changes of the p yielded dissociation constants (and thus binding energies) for the anions, which were related to the Stokes radii. The data fit the predictions of electrostatic interaction between the anions and the positive chargeassociated with site I, if the latter is located within a few angstroms from thesurface of the protein. The specificity of site I toward various anions is quantitatively explained by thedifferences in the change of Born energy upon transfer of the anions from water to the binding site. The changes in the deprotonation energy of the Schiff base upon the binding of anions, AAGdeprot, could be calculated from the ApKa at infinite anion concentration. Unexpectedly, the