MEMBRANE POTENTIAL-DEPENDENT REDUCTION OF CYTOCHROME-B-6 IN AN ALGAL MUTANT LACKING PHOTOSYSTEM-I CENTERS
MEMBRANE POTENTIAL-DEPENDENT REDUCTION OF CYTOCHROME-B-6 IN AN ALGAL MUTANT LACKING PHOTOSYSTEM-I CENTERS
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DOI：
10.1016/0005-2728(83)90220-7
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发表时间：
1983-01-01
期刊：
影响因子：
--
通讯作者：
LAVERGNE, J
中科院分区：
文献类型：
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作者：
LAVERGNE, J
研究了绿色小球藻（Chlorella sorokiniana）的一个光系统I（PS I）中心缺失和捕光复合物缺失的双突变株在光照下的吸收变化。观察到细胞色素B-6的减少，这似乎是相关的膜电位;细胞色素B-6的黑暗再氧化线性衰减的字段，和光诱导的减少被抑制的离子载体崩溃的膜电位。在饱和浓度的3-（3，4-二氯苯基）-1，1-二甲基脲的存在下，在1次闪光后也观察到这种场依赖性的减少，从而阻断了来自PS II的电子注入。细胞色素B-6的还原显然是由膜电位依赖的氧化还原平衡与一个未知的载体，G，这是已经减少在黑暗适应状态。当使用苯醌处理的藻类，G出现在黑暗中被氧化，使PS II的还原剂需要观察到的领域驱动的细胞色素B-6的还原。对光谱的分析表明，在420 nm附近吸收的增加归因于G的减少。G的中点电位，它在膜内的位置和它在电子转移链中的可能作用进行了讨论。
Absorption changes induced by illumination of a double mutant strain of the green alga Chlorella sorokiniana, lacking Photosystem (PS) I centers and deficient in light-harvesting complex, were investigated. A reduction of cytochrome b-6 was observed, which appeared to be correlated to the membrane potential; the dark reoxidation of cytochrome b-6 followed linearly the decay of the field, and the light-induced reduction was inhibited by an ionophore collapsing the membrane potential. This field-dependent reduction was also observed after 1 flash in the presence of a saturating concentration of 3-(3,4-dichlorophenyl)-1,1-dimethylurea, blocking the electron injection from PS II. The reduction of cytochrome b-6 is apparently controlled by a membrane potential-dependent redox equilibrium with an unknown carrier, G, which is already reduced in the dark-adapted state. When benzoquinone-treated algae were used, G appeared to be oxidized in the dark so that reductants from PS II were required to observe the field-driven reduction of cytochrome b-6. Analysis of the spectra allowed the ascription of an absorption increase around 420 nm to the reduction of G. The midpoint potential of G, its location within the membrane and its possible role in the electron-transfer chain are discussed.