Energy equilibration and primary charge separation in chlorophyll d-based photosystem I reaction center isolated from Acaryochloris marina

• Published in: FEBS letters Vol. 530; no. 1; pp. 153 - 157
• Main Authors: Kumazaki, Shigeichi, Abiko, Kazuki, Ikegami, Isamu, Iwaki, Masayo, Itoh, Shigeru
• Format: Journal Article
• Language: English
• Published: England Elsevier B.V 23.10.2002
• Subjects: Acaryochloris marina; Charge separation; Chl, chlorophyll; Chlorophyll - chemistry; Chlorophyll - isolation & purification; Chlorophyll d; Cyanobacteria - chemistry; DAS, decay-associated spectrum; FWHM, full width at half maximum; IRF, instrument-response function; P700, electron donor chlorophyll in plant/cyanobacterial PS I; P740, electron donor chlorophyll in A. marina PS I; PB/SE, photobleaching and/or stimulated emission; Photosynthesis; Photosynthetic Reaction Center Complex Proteins - chemistry; Photosynthetic Reaction Center Complex Proteins - isolation & purification; Photosystem I; PS I, photosystem I; PS II, photosystem II; RC, reaction center; Reaction center; RC, reaction center; Acaryochloris marina; Reaction center; Charge separation; Photosystem I; IRF, instrument-response function; Chl, chlorophyll; Chlorophyll d; PB/SE, photobleaching and/or stimulated emission; PS II, photosystem II; P700, electron donor chlorophyll in plant/cyanobacterial PS I; PS I, photosystem I; P740, electron donor chlorophyll in A. marina PS I; Photosynthesis; FWHM, full width at half maximum; DAS, decay-associated spectrum
• ISSN: 0014-5793; 1873-3468
• DOI: 10.1016/S0014-5793(02)03446-4

Primary photochemistry in photosystem I (PS I) reaction center complex from Acaryochloris marina that uses chlorophyll d instead of chlorophyll a has been studied with a femtosecond spectroscopy. Upon excitation at 630 nm, almost full excitation equilibration among antenna chlorophylls and 40% of the excitation quenching by the reaction center are completed with time constants of 0.6(±0.1) and 4.9(±0.6) ps, respectively. The rise and decay of the primary charge-separated state proceed with apparent time constants of 7.2(±0.9) and 50(±10) ps, suggesting the reduction of the primary electron acceptor chlorophyll (A 0) and its reoxidation by phylloquinone (A 1), respectively.