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High‐resolution triplet‐minus‐singlet absorbance difference spectrum of photosystem II particles
Author(s) -
den Blanken H.J.,
Hoff A.J.,
Jongenelis A.P.J.M.,
Diner B.A.
Publication year - 1983
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/0014-5793(83)81108-9
Subject(s) - absorbance , singlet state , dimer , photosystem ii , triplet state , chemistry , photosystem i , photochemistry , crystallography , nuclear magnetic resonance , physics , atomic physics , photosynthesis , molecule , excited state , biochemistry , organic chemistry , chromatography
The triplet state of the primary donor of photosystem II particles prepared from a mutant of Chlamydomonas reinhardtii has been studied at 1.2 K with absorbance‐detected ESR in zero‐magnetic field (ADMR). Two sets of resonances with slightly different zero‐field splitting parameters | D | and | E | were observed, | D | = 285.5, | E | = 38.8 and | D | = 288.8 × 10 −4 cm −1 , | E | = 42.2 × 10 −4 cm −1 , respectively. Both sets of | D | and | E | values are close to those found for P T ‐700, as are the sublevel decay rates k x = 930 ± 40, k y = 1088 ± 50 and k z = 110 ± 5 s −1 . The AMDR‐detected triplet‐minus‐singlet absorbance difference spectrum of P T ‐680 is very similar to that of P T ‐700 and closely resembles that of covalently connected Chl a dimers in vitro. We conclude that P‐680 is a Chl a dimer whose general structure is similar to that of P‐700.