CORRELATION OF PHOTOCHEMICAL CYCLE, H+ RELEASE AND UPTAKE, AND ELECTRIC EVENTS IN BACTERIORHODOPSIN
CORRELATION OF PHOTOCHEMICAL CYCLE, H+ RELEASE AND UPTAKE, AND ELECTRIC EVENTS IN BACTERIORHODOPSIN
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DOI：
10.1016/0014-5793(84)80628-6
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发表时间：
1984-01-01
期刊：
影响因子：
3.5
通讯作者：
SKULACHEV, VP
中科院分区：
文献类型：
--
作者：
DRACHEV, LA;KAULEN, AD;SKULACHEV, VP
比较了细菌视紫红质3种光诱导反应的动力学：光谱变化，开放紫色膜片悬浮液中的pH值变化以及将这些膜片纳入脂质浸渍的胶膜所产生的电势。在ph缓冲液存在的情况下，细菌的H+释放被证明与M412中间体的形成和电位生成的微秒相有关。当溶液离子强度较高时，H+/M412的比值为0.7±0.1。在没有缓冲的情况下，H+释放被证明比光谱和电响应慢得多。在pH缓冲液存在和不存在的情况下，细菌紫质对H+的吸收动力学接近于M412衰变和电相毫秒相。细菌视紫红质诱导的质子释放期约占总电位的20%，而摄取期约占总电位的80%。这与假设质子起始点（可能是连接赖氨酸216和视网膜的质子化希夫碱）更靠近细菌膜的外部而不是内部（细胞质）表面的模型是一致的。
The kinetics of 3 photoinduced responses of bacteriorhodopsin have been compared: spectral changes, pH shifts in a suspension of open purple membrane sheets and electric potential generation by the sheets incorporated into a lipid-impregnated collodion film. In the presence of a pH-buffer, the H+release by bacteriorhodops in was shown to correlate with the formation of the M412 intermediate and the microsecond phase of the potential generation. The H+/M412 ratio is equal to 0.7±0.1 if the ionic strength of the solution is high. In the absence of the buffer, the H+release proved to be much slower than spectral and electric responses. The kinetics of H+uptake by bacteriorhodopsin is close to M412 decay and to the electrogeneous millisecond phase in both the presence and absence of the pH buffer. The bacteriorhodopsin-induced proton release phase accounts for about 20%, and the uptake phase for about 80% of the overall potential. This is compatible with the model assuming that the proton start-out point - possibly, the protonated Schiff base connecting lysine 216 with retinal - is closer to the outer rather than the inner (cytoplasmic) surface of the bacterial membrane.