Frank H A, McLean M B, Sauer K
Proc Natl Acad Sci U S A. 1979 Oct;76(10):5124-8. doi: 10.1073/pnas.76.10.5124.
We report light-induced electron paramagnetic resonance triplet spectra from samples of chloroplasts or digitonin photosystem I particles that depend upon the dark redox state of the bound acceptors of photosystem I. If the reaction centers are prepared in the redox state P-700 A X- FdB-FdA-, then upon illumination at 11K we observe a polarized chlorophyll triplet species which we interpret as arising from radical pair recombination between P-700+ and A-. This chlorophyll triplet is apparently the analog of the PR state of photosynthetic bacteria [Parson, W.W. & Cogdell, R.J. (1975) Biochim. Biophys. Acta 416, 105-149]. If the reaction centers are prepared in the dark redox state P-700 A X FdB-FdA-, then upon illumination at 11K we observe a different triplet species of uncertain origin, possibly pheophytin or carotenoid. This species is closely associated with the photosystem I reaction center and it traps excitation when P-700 is oxidized.
我们报道了来自叶绿体或洋地黄皂苷光系统I颗粒样品的光诱导电子顺磁共振三重态光谱,这些光谱取决于光系统I结合受体的暗氧化还原状态。如果反应中心制备成氧化还原状态P-700 A X- FdB-FdA-,那么在11K光照下,我们观察到一种极化的叶绿素三重态物种,我们将其解释为P-700+与A-之间的自由基对重组产生的。这种叶绿素三重态显然是光合细菌PR状态的类似物[帕森,W.W. & 科格德尔,R.J.(1975年)《生物化学与生物物理学报》416,105 - 149]。如果反应中心制备成暗氧化还原状态P-700 A X FdB-FdA-,那么在11K光照下,我们观察到一种来源不确定的不同三重态物种,可能是脱镁叶绿素或类胡萝卜素。该物种与光系统I反应中心密切相关,并且当P-700被氧化时会捕获激发。