Energy transfer processes in the isolated core antenna complexes CP43 and CP47 of photosystem II

• Published in: Biochimica et biophysica acta Vol. 1797; no. 9; pp. 1606 - 1616
• Main Authors: Casazza, Anna Paola, Szczepaniak, Malwina, Müller, Marc G., Zucchelli, Giuseppe, Holzwarth, Alfred R.
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier B.V 01.09.2010
• Subjects: antenna complexes; Energy Transfer; femtosecond absorption; Fluorescence; fluorescence kinetics; Kinetics; Light-Harvesting Protein Complexes - chemistry; photosynthesis; photosystem II; Photosystem II Protein Complex - chemistry; Zea mays - enzymology; femtosecond absorption; Chl; PSII; energy transfer; fluorescence kinetics; β-DM; antenna complexes; RC; photosystem II; EET; photosynthesis; DAS; Mes; SAES; SADS
• ISSN: 0005-2728; 0006-3002; 1879-2650
• DOI: 10.1016/j.bbabio.2010.05.008

The energy equilibration and transfer processes in the isolated core antenna complexes CP43 and CP47 of photosystem II have been studied by steady-state and ultrafast (femto- to nanosecond) time-resolved spectroscopy at room temperature. The annihilation-free femtosecond absorption data can be described by surprisingly simple sequential kinetic models, in which the excitation energy transfer between blue and red states in both antenna complexes is dominated by sub-picosecond processes and is completed in less than 2 ps. The slowest energy transfer steps with lifetimes in the range of 1–2 ps are assigned to transfer steps between the chlorophyll layers located on the stromal and lumenal sides. We conclude that these ultrafast intra-antenna energy transfer steps do not represent a bottleneck in the rate of the primary processes in intact photosystem II. Since the experimental energy equilibration rates are up to a factor of 3–5 higher than concluded previously, our results challenge the conclusions drawn from theoretical modeling.