An electron paramagnetic resonance investigation of the electron transfer reactions in the chlorophyll d containing photosystem I of Acaryochloris marina

• Published in: FEBS letters 2007-04, Vol.581 (8), p.1567-1571
• Main Authors: Santabarbara, Stefano, Chen, Min, Larkum, Anthony W.D., Evans, Michael C.W.
• Format: Article
• Language: English
• Subjects: a quinone secondary electron acceptor; Acaryochloris marina; Chl d(a); Chlorophyll - chemistry; Chlorophyll - radiation effects; Chlorophyll d; Chlorophyll d(a); Cold Temperature; Cyanobacteria - metabolism; electron paramagnetic resonance; electron spin echo; electron spin echo envelope modulation; Electron Spin Resonance Spectroscopy; Electron transfer reactions; Electron Transport; EPR; ESE; ESEEM; Iron–sulphur centres; Kinetics; Light; OOP; out-of-phase; P 740 + ( P 700 + ); Photosystem I; Photosystem I Protein Complex - chemistry; Photosystem I Protein Complex - radiation effects; Primary donor (cation); PS I; Radical pairs; SFT; sine Fourier transform
• ISSN: 0014-5793; 1873-3468
• DOI: 10.1016/j.febslet.2007.03.014

Electron paramagnetic resonance (EPR) spectroscopy reveals functional and structural similarities between the reaction centres of the chlorophyll d-binding photosystem I (PS I) and chlorophyll a-binding PS I. Continuous wave EPR spectrometry at 12 K identifies iron–sulphur centres as terminal electron acceptors of chlorophyll d-binding PS I. A transient light-induced electron spin echo (ESE) signal indicates the presence of a quinone as the secondary electron acceptor (Q) between P 740 + and the iron–sulphur centres. The distance between P 740 + and Q − was estimated within point-dipole approximation as 25.23 ± 0.05 Å, by the analysis of the electron spin echo envelope modulation.