期刊名称：Proceedings of the National Academy of Sciences
印刷版ISSN：0027-8424
电子版ISSN：1091-6490
出版年度：1977
卷号：74
期号：9
页码：3826-3830
DOI：10.1073/pnas.74.9.3826
语种：English
出版社：The National Academy of Sciences of the United States of America
摘要：Electron paramagnetic resonance spectrometry was used to investigate, at physiological temperatures, light-induced electron transport from membrane-bound iron-sulfur components (bound ferredoxin) to soluble ferredoxin and NADP+ in membrane fragments (from the blue-green alga, Nostoc muscorum) that had high rates of electron transport from water to NADP+ and from an artificial electron donor, reduced dichlorophenolindophenol (DCIPH2) to NADP+. Illumination at 20{degrees} resulted in the photoreduction of membrane-bound iron-sulfur centers A and B. Photoreduction by water gave electron paramagnetic resonance signals of both centers A and B; photoreduction by DCIPH2 was found to generate a strong electron paramagnetic signal of only center B. When water was the reductant, the addition and photoreduction of soluble ferredoxin generated additional signals characteristics of soluble ferredoxin without causing a decrease in the amplitude of the signals due to centers A and B. The further addition of NADP+ (and its photoreduction) greatly diminished signals due to the bound iron-sulfur centers and to soluble ferredoxin. An outflow of electrons from center B to soluble ferredoxin and NADP+ was particularly pronounced when DCIPH2 was the reductant. These observations provide the first evidence for a light-induced electron transport between membrane-bound iron-sulfur centers and ferredoxin-NADP+. The relationship of these observations to current concepts of photosynthetic electron transport is discussed.
关键词：photosynthesis ; reducing power ; electron carriers
