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DETECTION OF ONE SL...
DETECTION OF ONE SLOWLY EXCHANGING SUBSTRATE WATER MOLECULE IN THE S-3 STATE OF PHOTOSYSTEM-II
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- Messinger, Johannes, 1963- (författare)
- Research School of Biological Sciences, Australian National University, Canberra, Australia
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BADGER, M (författare)
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WYDRZYNSKI, T (författare)
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(creator_code:org_t)
- 1995-04-11
- 1995
- Engelska.
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Ingår i: Proceedings of the National Academy of Sciences of the United States of America. - : NATL ACAD SCIENCES. - 0027-8424 .- 1091-6490. ; 92:8, s. 3209-3213
- Relaterad länk:
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http://www.pnas.org/...
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visa fler...
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https://urn.kb.se/re...
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https://doi.org/10.1...
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Abstract
Ämnesord
Stäng
- The exchangeability of the substrate water molecules at the catalytic site of water oxidation in photosystem II has been probed by isotope-exchange measurements using mass spectrometric detection of flash-induced oxygen evolution. A stirred sample chamber was constructed to reduce the lag time between injection of (H2O)-O-18 and the detecting flash by a factor of more than 1000 compared to the original experiments by R. Radmer and O. Ollinger [(1986) FEBS Lett. 195, 285-289]. Our data show that there is a slow (t(1/2) approximate to 500 ms, 10 degrees C) and a fast (t(1/2) < 25 ms, 10 degrees C) exchanging substrate water molecule in the S-3 State of photosystem II. The slow exchange is coupled with an activation energy of about 75 kJ/mol and is discussed in terms of a terminal manganese oxo ligand, while the faster exchanging substrate molecule may represent a water molecule not directly bound to the manganese center.
Ämnesord
- NATURVETENSKAP -- Biologi -- Biokemi och molekylärbiologi (hsv//swe)
- NATURAL SCIENCES -- Biological Sciences -- Biochemistry and Molecular Biology (hsv//eng)
Nyckelord
- PHOTOSYNTHESIS
- OXYGEN EVOLUTION
- (H2O)-O-16/(H2O)-O-18 ISOTOPE EXCHANGE
- MASS SPECTROMETRY
- CHEMISTRY OF WATER OXIDATION
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