Ultrafast chlorophyll b‐chlorophyll a excitation energy transfer in the isolated light harvesting complex, LHC II, of green plants

FEBS Letters

Pålsson, Lars Olof²  Gulbinas, Vidmantas²  Spangfort, Michael D.¹  Gillbro, Tomas² 

[1] Department of Biochemistry, Chemical center. University of Lund, PoB 124, S-221 00 Lund, Sweden;Department of Physical Chemistry, University of Umeå, S-901 87 Umeå, Sweden

关键词: Chlorophyll a;    Chlorophyll b;    Energy transfer;    Light-harvesting complex;    Femtosecond spectroscopy;    Anisotropy;    Photosystem 2;    LHC II;    Chl;    Chlorophyll;    LHC II;    light-harvesting chlorophyll a/b-protein complex of photosystem 2;    PS II;    photosystem 2;    OGP;    n-octyl-β-d-glucopyranoside;    DM;    dodecylmaltoside;   

DOI  :  10.1016/0014-5793(94)80400-1

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

The excitation energy transfer between chlorophyll b (Chl b) and chlorophyll a (Chl a) in the isolated trimeric chlorophyll-a/b-binding protein complex of spinach photosystem 2 (LHC II) has been studied by femtosecond spectroscopy. In the main absorption band of Chl b the ground state recovery consists of two components of 0.5 ps and 2.0 ps, respectively. Also in the Chl a absorption band, at 665 nm, the ground state recovery is essentially bi-exponential. In this case is, however, the fastest relaxation lifetime is a 2.0 ps component followed by a slower component with a lifetime in the order of 10–20 ps. In the Chl b absorption band a more or less constant anisotropy of r = 0.2 was observed during the 3 ps the system was monitored. In the Chl a absorption band there was, however, a relaxation of the anisiotropy from r = 0.3 to a quasi steady state level of r = 0.18 in about 1 ps. Since the 0.5 ps component is only seen upon selective excitation of Chl b we assign this component to the energy transfer between Chl b and Chl a. The other components most likely represents redistribution processes of energy among spectrally different forms of Chl a. The energy transfer process between Chl b and Chl a can well be explained by the Förster mechanism which also gives a calculated distance of 13 Å between interacting chromophores. The organisation of chlorophylls in LHC II is discussed in view of the recent crystal structure data (1991) Nature 350, 130].

【 授权许可】

Unknown