Proton and hydrogen currents in photosynthetic water oxidation.
Proton and hydrogen currents in photosynthetic water oxidation.
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DOI：
10.1016/s0005-2728(00)00069-4
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发表时间：
2000-05
期刊：
影响因子：
--
通讯作者：
Cecilia Tommos;Gerald T. Babcock
中科院分区：
文献类型：
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作者：
Cecilia Tommos;Gerald T. Babcock
导致水氧化的光合作用过程涉及从光子动力学到光化学驱动的电子转移到耦合电子/质子化学的时间演变。具有氧化还原活性的酪氨酸YZ是水氧化所必需的质子流的启动元件，本文讨论了YZ的这一功能的热力学和动力学意义。这些考虑也提供了深入了解的相关角色的YZ在保持光系统II（PSII）的光化学量子效率高，并保存在PSII反应中心的光化学产生的高氧化条件。YZ的氧化P680+可以很好地描述的处理，调用质子耦合的背景下的非绝热电子转移。然而，YZ的还原似乎是通过绝热过程进行的，该过程可能具有氢原子转移的特征。
The photosynthetic processes that lead to water oxidation involve an evolution in time from photon dynamics to photochemically-driven electron transfer to coupled electron/proton chemistry. The redox-active tyrosine, YZ, is the component at which the proton currents necessary for water oxidation are switched on. The thermodynamic and kinetic implications of this function for YZare discussed. These considerations also provide insight into the related roles of YZin preserving the high photochemical quantum efficiency in Photosystem II (PSII) and of conserving the highly oxidizing conditions generated by the photochemistry in the PSII reaction center. The oxidation of YZby P680+can be described well by a treatment that invokes proton coupling within the context of non-adiabatic electron transfer. The reduction of YZ, however, appears to proceed by an adiabatic process that may have hydrogen-atom transfer character.