THE MANGANESE SITE OF THE PHOTOSYNTHETIC WATER-SPLITTING ENZYME
THE MANGANESE SITE OF THE PHOTOSYNTHETIC WATER-SPLITTING ENZYME
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DOI：
10.1126/science.2916124
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发表时间：
1989-02-10
期刊：
影响因子：
56.9
通讯作者：
CRAMER, SP
中科院分区：
文献类型：
--
作者：
GEORGE, GN;PRINCE, RC;CRAMER, SP
作为我们大气中氧气的起源，叶绿体的光合水分解酶对地球上的有氧生命至关重要。它在其活性部位有一个锰簇，但在分子水平上知之甚少。利用偏振同步辐射研究了锰在定向叶绿体中的x射线吸收。锰的网站，在“休息”（S1）状态，是一个不对称的集群，其中可能包含四个锰原子，与原子间的间距为2.7和3.3埃;由3.3埃锰对形成的矢量是定向垂直于膜平面。与模型化合物的比较表明，簇包含连接锰原子的桥接氧化物或氢氧化物配体，可能与连接3.3埃锰对的羧酸桥。
As the originator of the oxygen in our atmosphere, the photosynthetic water -splitting enzyme of chloroplasts is vital for aerobic life on the earth. It has a manganese cluster at its active site, but it is poorly understood at the molecular level. Polarized synchrotron radiation was used to examine the x-ray absorption of manganese in oriented chloroplasts. The manganese site, in the "resting" (S1) state, is an asymmetric cluster, which probably contains four manganese atoms, with interatomic separations of 2.7 and 3.3 angstroms; the vector formed by the 3.3-angstrom manganese pair is oriented perpendicular to the membrane plane. Comparisons with model compounds suggest that the cluster contains bridging oxide or hydroxide ligands connecting the manganese atoms, perhaps with carboxylate bridges connecting the 3.3-angstrom manganese pair.