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Secondary structure and thermal stability of the extrinsic 23 kDa protein of photosystem II studied by Fourier transform infrared spectroscopy
Author(s) -
Zhang Haoming,
Ishikawa Yasuo,
Yamamoto Yasusi,
Carpentier Robert
Publication year - 1998
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/s0014-5793(98)00371-8
Subject(s) - photosystem ii , fourier transform infrared spectroscopy , fourier transform , infrared , thermal stability , chemistry , spectroscopy , analytical chemistry (journal) , photosystem i , fourier transform spectroscopy , biophysics , materials science , biology , physics , photosynthesis , optics , biochemistry , chromatography , astronomy , organic chemistry , quantum mechanics
The secondary structure and thermal stability of the extrinsic 23 kDa protein (OEC23) of spinach photosystem II have been characterized in solution between 25 and 75°C using Fourier transform infrared spectroscopy. Quantitative analysis of the amide I band (1700–1600 cm −1 ) shows that OEC23 contains 5% α‐helix, 37% β‐sheet, 24% turn, and 34% disorder structures at 25°C. No appreciable conformational changes occur below 45°C. At elevated temperatures, the β‐sheet structure is unfolded into the disorder structure with a major conformational transition occurring at 55°C. Implications of these results for the functions of OEC23 in photosystem II are discussed.