Studies on early events of photosynthetic electron transport---functions of Fe,Ca and M

光合电子传递早期事件的研究——Fe、Ca、M的功能

基本信息

批准号：
63440002
负责人：
KATOH Sakae
金额：
$ 1.22万
依托单位：
University of Tokyo
依托单位国家：
日本
项目类别：
Grant-in-Aid for General Scientific Research (A)
财政年份：
1988
资助国家：
日本
起止时间：
1988 至 1989
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-63440002/
关键词：
Photosynthesis Electron transport Photosystem II Oxygen evolution Calcium Extrinsic 23 kDa protein NaCl treatment Iron 酸処理 23KDa蛋白質系1反応中心酸素発生反応 23kDaたんぱく質光化学系I 鉄イオウセンター

项目摘要

1. The number and function of Ca involved in photosystem II (PS II) electron transport were studied with oxygen evolving preparations isolated from rice and spinach. (1) PS II oxygen evolving membranes contained two Ca per PS II, which are heterogenous in binding affinity. A loosely bound Ca could be solubilized by detergent-treatments and the resulting PS II complexes containing only one Ca were highly active in oxygen evolution. Thus only one bound Ca is needed for PS II electron transport. (2) Treatment of PS II preparations with high concentrations of NaCl did not solubilize Ca, even though the treatment resulted in a strong inactivation of oxygen evolution and the lost activity was restored by added Ca. (3) A brief treatment at pH 3.0, which caused liberation of one out of the two Cabound to PS II membranes, failed to extract Ca from PS II complexes containing one Ca but induced Ca-reversible inactivation of oxygen evolution. This indicates that the acid-extractable Ca is not need … More ed for oxygen evolution. (4) The extrinsic 23 kDa protein was found to decrease the binding affinity of added Ca to pH 3.0- treated PS II preparations. (5) The above results are inconsistent with the view that NaCl- and pH 3.0-treatments inhibit oxygen evolution by extracting bound Ca and that the 23 kDa protein stabilizes or protects Ca in PS II preparation. Instead, detailed investigation on Ca concentration dependence of oxygen evolution in NaCl- and pH 3.0-treated preparations strongly suggest that the two treatments share a common mechanism of inactivation,i.e., a conformational change of the oxygen evolving complex.2. Crosslinking experiments showed that the extrinsic 33 kDa protein is located near the chlbinding 47 kDa protein and the association of the 33 kDa protein protects Mn against alkaline pH-treatment.3. Purified PS II reaction center complexes and D1-D2-cytochrome b559 complexes from the thermophilic cyanobacterium S. elongatus were found to contain one iron atom of unknown function in addition to a heme iron of cytochrome b559 and a non-heme iron locating near Q_A and Q_B. Less

1。对光系统II（PS II）的CA的数量和功能进行了研究，并研究了从大米和菠菜中分离出的氧气进化制剂。（1）PS II氧气不断发展的机制包含两个CA，PS II，在结合亲和力中是异质的。通过确定治疗可以溶解一个松散的结合Ca，所得的PS II复合物仅包含一个Ca的氧气进化高度活跃。 PS II电子传输只需要一个结合的Ca。（2）高浓度NaCl的PS II制剂的处理并不能溶于Ca，即使治疗导致强烈失活的氧气进化，并且添加的Ca恢复了损失的活性。（3）在pH 3.0处进行短暂处理，导致两个CABOUND到PS II机制中的一个释放，未能从含有一个CA但诱导CA可逆的氧气灭活的PS II配合物中提取Ca。这表明不需要酸提取的Ca……更多地用于氧气进化。（4）发现外部23 kDa蛋白可降低Ca与pH 3.0处理的PS II制剂的结合亲和力。（5）上述结果与NaCl-和pH 3.0处理的观点不一致，通过提取结合的Ca抑制氧气的进化，并且23 kDa蛋白可以在PS II制备中稳定或保护Ca。取而代之的是，对NaCl-和pH 3.0处理的制剂中氧气进化的CA浓度依赖性的详细研究强烈表明，两种治疗方法具有灭活的共同机制，即氧气进化复合物的构象变化。2。交联实验表明，外部33 kDa蛋白位于Chlbinding 47 kDa蛋白附近，33 kDa蛋白的缔合可保护MN免受碱性pH-Tracterment.3。发现来自嗜热蓝细菌链球菌链球菌的纯化的PS II反应中心配合物和D1-D2-环形B559复合物，除了具有细胞色素B559的血红素铁外，还包含一个未知功能的铁原子，以及附近Q_A和Q_B附近的非头部铁的铁原子。较少的