Brudvig G W, Crabtree R H
Proc Natl Acad Sci U S A. 1986 Jul;83(13):4586-8. doi: 10.1073/pnas.83.13.4586.
We present a mechanism for photosynthetic O2 evolution based on a structural conversion of a Mn4O6 "adamantane"-like complex to a Mn4O4 "cubane"-like complex. EPR spectral data obtained from the S2 state of the O2-evolving complex are characteristic of a Mn4O4 cubane-like structure. Based on this structure for the manganese complex in the S2 state as well as a consideration of the other evidence available on the natural system and the coordination chemistry of manganese, structures are proposed for the five intermediate oxidation states of the manganese complex. A molecular mechanism for the formation of an O--O bond and the displacement of O2 from the S4 state is easily accommodated by the proposed model. The model is discussed in terms of recent EPR, x-ray, and UV spectral data obtained from the manganese site in the photosynthetic O2-evolving complex.
我们提出了一种基于Mn4O6“金刚烷”样复合物向Mn4O4“立方烷”样复合物结构转变的光合放氧机制。从放氧复合物的S2状态获得的电子顺磁共振（EPR）光谱数据是Mn4O4立方烷样结构的特征。基于S2状态下锰复合物的这种结构，以及对自然系统中现有其他证据和锰的配位化学的考虑，提出了锰复合物五个中间氧化态的结构。所提出的模型很容易解释O—O键形成和O2从S4状态位移的分子机制。根据从光合放氧复合物中锰位点获得的最新EPR、X射线和紫外光谱数据对该模型进行了讨论。
