TEMPERATURE-DEPENDENCE OF P680+ REDUCTION IN O-2-EVOLVING PS-II MEMBRANE-FRAGMENTS AT DIFFERENT REDOX STATES SI OF THE WATER OXIDIZING SYSTEM
TEMPERATURE-DEPENDENCE OF P680+ REDUCTION IN O-2-EVOLVING PS-II MEMBRANE-FRAGMENTS AT DIFFERENT REDOX STATES SI OF THE WATER OXIDIZING SYSTEM
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DOI：
10.1016/0014-5793(88)80070-x
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发表时间：
1988-08-29
期刊：
影响因子：
3.5
通讯作者：
RENGER, G
中科院分区：
文献类型：
--
作者：
ECKERT, HJ;RENGER, G
在248<T< 295 K的温度范围内，通过测量由激光闪光在830 nm处诱导的暗适应的释放O2的菠菜PS II膜片段的吸收变化，分析了从Z到P680+的电子转移动力学作为温度的函数。结果发现：（1）在270<T<295 K的生理温度范围内，P680+还原动力学及其对水氧化催化位氧化还原态Si的依赖性受温度的影响很小。(ii)在248<T<295 K的暗弛豫态S下，Z到P680+的电子转移活化能约为10 kJ/mol。(iii)在第二次和随后的闪光中，P680+和Q−A之间稳定电荷分离的能力在-10 °C以下显著降低。这种现象被认为是由于温度对电子从Q-A转移到QB的强烈影响。结果进行了简要讨论，在PS II中的电子转移步骤的反应坐标的D-1/D-2多肽复合物的结构变化的可能影响。
The electron transfer kinetics from Z to P680+was analyzed as a function of temperature in the range of 248<T< 295 K by measuring absorption changes induced at 830 nm by a laser flash train in dark adapted O2evolving PS II membrane fragments from spinach. It was found: (i) that the kinetics of P680+reduction and their dependence on the redox state Siof the catalytic site of water oxidation are only slightly affected by temperature within the physiological range of 270<T<295 K. (ii) In the dark relaxed state S, the electron transfer from Z to P680+exhibits an activation energy of the order of 10 kJ/mol in 248<T<295 K. (iii) In the 2nd and subsequent flashes of the train the ability for a stable charge separation between P680+and Q−A, markedly decreases below −10°C. This phenomenon is assumed to be due to a strong effect of temperature on the electron transfer from Q−Ato QB. The results are briefly discussed in relation to possible effects of structural changes in the D-1/D-2 polypeptide complex on the reaction coordinate of electron transfer steps in PS II.