Malkin R, Bearden A J
Proc Natl Acad Sci U S A. 1971 Jan;68(1):16-9. doi: 10.1073/pnas.68.1.16.
An electron paramagnetic resonance signal was observed at 25 degrees K in whole spinach chloroplasts after illumination at 77 degrees K. The light-induced epr spectrum had g-values (g(x) = 1.86, g(y) = 1.94, g(z) = 2.05) and a temperature dependence that were characteristic of the reduced state of a plant-type ferredoxin. The light-induced epr spectrum was also observed in broken spinach chloroplasts from which soluble ferredoxin was removed. Chemical analyses showed that both whole and broken spinach chloroplasts contained amounts of nonheme iron and "acid-labile sulfide" consistent with the presence of a bound iron-sulfur protein, at a level of about one molecule per 75 chlorophyll molecules. These results support the conclusion that chloroplasts contain a bound ferredoxin that may serve as a primary low-potential electron acceptor in photosynthesis.
在77K光照后,于25K的完整菠菜叶绿体中观察到电子顺磁共振信号。光诱导的电子顺磁共振谱具有g值(g(x)=1.86,g(y)=1.94,g(z)=2.05)以及温度依赖性,这些是植物型铁氧化还原蛋白还原态的特征。在去除了可溶性铁氧化还原蛋白的破碎菠菜叶绿体中也观察到了光诱导的电子顺磁共振谱。化学分析表明,完整和破碎的菠菜叶绿体都含有一定量的非血红素铁和“酸不稳定硫化物”,这与存在结合型铁硫蛋白一致,其含量约为每75个叶绿素分子一个分子。这些结果支持了叶绿体含有一种结合型铁氧化还原蛋白的结论,该蛋白可能在光合作用中作为主要的低电位电子受体。