The S sub 3 state of photosystem II: Differences between the structure of the manganese complex in the S sub 2 and S sub 3 states determined by X-ray absorption spectroscopy

Journal Article · Tue Jan 16 04:00:00 EST 1990 · Biochemistry; (USA)

DOI:https://doi.org/10.1021/bi00454a023· OSTI ID:6710223

Guiles, R D; Zimmermann, J L; McDermott, A E; Yachandra, V K; Cole, J L; Dexheimer, S L; Britt, R D; Sauer, K; Klein, M P ^[1]; Wieghardt, K; Bossek, U ^[2]

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1. Lawrence Berkeley Laboratory, CA (USA)
2. Ruhr-Universitaet-Bochum (West Germany)

O{sub 2}-evolving photosystem II (PSII) membranes from spinach have been cryogenically stabilized in the S{sub 3} state of the oxygen-evolving complex. The cryogenic trapping of the S{sub 3} state was achieved using a double-turnover illumination of dark-adapted PSII preparations maintained at 240 K. A double turnover of PSII was accomplished using the high-potential acceptor, Q{sub 400}, which is the high-spin iron of the iron-quinone acceptor complex. EPR spectroscopy was the principal tool establishing the S-state composition and defining the electron-transfer events associated with a double turnover of PSII. The inflection point energy of the Mn X-ray absorption K-edge of PSII preparations poised in the S{sub 3} state is the same as for those poised in the S{sub 2} state. This is surprising in light of the loss of the multiline EPR signal upon advancing to the S{sub 3} state. This indicates that the oxidative equivalent stored within the oxygen-evolving complex (OEC) during this transition resides on another intermediate donor which must be very close to the manganese complex. An analysis of the Mn extended x-ray absorption fine structure (EXAFS) of PSII preparations poised in the S{sub 2} and S{sub 3} states indicates that a small structural rearrangement occurs during this photoinduced transition. A detailed comparison of the Mn EXAFS of these two S states with the EXAFS of four multinuclear {mu}-oxo-bridged manganese compounds indicates that the photosynthetic manganese site most probably consists of a pair of binuclear di-{mu}-oxo-bridged manganese structures.

• DOE Contract Number: AC03-76SF00098
• OSTI ID: 6710223
• Journal Information: Biochemistry; (USA), Journal Name: Biochemistry; (USA) Vol. 29:2; ISSN 0006-2960; ISSN BICHA
• Country of Publication: United States
• Language: English

Related Subjects

14 SOLAR ENERGY
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Photobiological
& Thermochemical Conversion-- (1980-)
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400101 -- Activation
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59 BASIC BIOLOGICAL SCIENCES
ABSORPTION SPECTROSCOPY
COMPLEXES
ELECTRON SPIN RESONANCE
ELEMENTS
FINE STRUCTURE
FOOD
MAGNETIC RESONANCE
MAGNOLIOPHYTA
MAGNOLIOPSIDA
MANGANESE COMPLEXES
MEMBRANES
MOLECULAR STRUCTURE
NONMETALS
OXYGEN
PHOTOSYNTHETIC MEMBRANES
PHOTOSYNTHETIC REACTION CENTERS
PLANTS
RESONANCE
SPECTROSCOPY
SPINACH
TRANSITION ELEMENT COMPLEXES
VEGETABLES
X-RAY SPECTROSCOPY