TRIPLET-STATES IN PHOTOSYSTEM-I OF SPINACH-CHLOROPLASTS AND SUB-CHLOROPLAST PARTICLES

被引:80
作者
FRANK, HA [1 ]
MCLEAN, MB [1 ]
SAUER, K [1 ]
机构
[1] UNIV CALIF BERKELEY, DEPT CHEM, BERKELEY, CA 94720 USA
关键词
D O I
10.1073/pnas.76.10.5124
中图分类号
O [数理科学和化学]; P [天文学、地球科学]; Q [生物科学]; N [自然科学总论];
学科分类号
07 ; 0710 ; 09 ;
摘要
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.
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页码:5124 / 5128
页数:5
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