A D-band (130 GHz) EPR study of the primary electron donor triplet state in photosynthetic reaction centers of Rhodobacter sphaeroides R26.

Autor: Paschenko, S., Gast, P., Hoff, A.
Zdroj: Applied Magnetic Resonance; Dec2001, Vol. 21 Issue 3/4, p325-334, 10p
Abstrakt: A high-field (D-band, 130 GHz) electron spin echo-detected spectrum of the primary electron donor triplet state,3P, in quinone-depleted photosynthetic reaction centers from the bacterium Rhodobacter sphaeroides R26 is obtained. It shows a significant g-anisotropy, which is larger than that of the primary donor oxidized state, P+⋅. Simulation gives the triplet g-tensor principal values of 2.0037, 2.0028, and 2.0022 (precision ±0.0001), assuming that the g-tensor is coaxial to a zerofield splitting tensor. The3P spectral lineshape reveals an orientational anisotropy of the triplet quantum yield. We explain this anisotropy as arising from the difference in the main values and relative orientations between the g-tensors of P+⋅ and I in the primary radical pair (the triplet state’s precursor). [ABSTRACT FROM AUTHOR]
Databáze: Complementary Index
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