LIGHT-DRIVEN PROTONATION CHANGES OF INTERNAL ASPARTIC ACIDS OF BACTERIORHODOPSIN - AN INVESTIGATION BY STATIC AND TIME-RESOLVED INFRARED DIFFERENCE SPECTROSCOPY USING [4-C-13] ASPARTIC ACID LABELED PURPLE MEMBRANE
LIGHT-DRIVEN PROTONATION CHANGES OF INTERNAL ASPARTIC ACIDS OF BACTERIORHODOPSIN - AN INVESTIGATION BY STATIC AND TIME-RESOLVED INFRARED DIFFERENCE SPECTROSCOPY USING [4-C-13] ASPARTIC ACID LABELED PURPLE MEMBRANE
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DOI：
10.1021/bi00323a024
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发表时间：
1985-01-01
期刊：
影响因子：
2.9
通讯作者：
SIEBERT, F
中科院分区：
文献类型：
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作者：
ENGELHARD, M;GERWERT, K;SIEBERT, F
用时间分辨和静态红外差谱方法研究了盐生盐杆菌菌紫质（BR）光循环过程中的分子事件。特征光谱变化涉及质子化羧基的C = O伸缩振动进行了检测。为了鉴定具有Glu或Asp的相应基团，用[4- 13 C]Asp选择性标记BR。加入CA。[约] 70%。标记和未标记的BR的CO2伸缩振动的区域中的差异光谱的比较表明，电离的天冬氨酸的影响，在光循环，最早的效果已经观察到在K610中间。两者合计，结果提供的证据表明，4个内部天冬氨酸进行质子化的变化和一个谷氨酸，其余质子化，被干扰。结果进行了讨论有关的质子泵机制，如视网膜异构化，电荷分离，pK的变化，和质子通路的各个方面。
The molecular events during the photocycle of [Halobacterium halobium] bacteriorhodopsin [BR] were studied by the method of time-resolved and static infrared difference spectroscopy. Characteristic spectral changes involving the C.dbd.O stretching vibration of protonated carboxylic groups were detected. To identify the corresponding groups with either Glu or Asp, BR was selectively labeled with [4-13C]Asp. An incorporation of ca. [circa] 70% was obtained. The comparison of the difference spectra in the region of the CO2- stretching vibrations of labeled and unlabeled BR indicates that ionized Asp are influenced during the photocycle, the earliest effect being observed already at the K610 intermediate. Taken together, the results provide evidence that 4 internal Asp undergo protonation changes and that one Glu, remaining protonated, is disturbed. The results are discussed in relation to the various aspects of the proton pumping mechanism, such as retinal isomerization, charge separation, pK changes, and proton pathway.