TY - JOUR
T1 - Partial degradation of the 18-kDa protein of the photosynthetic oxygen-evolving complex
T2 - A study of a binding site
AU - Kuwabara, Tomohiko
AU - Murata, Teruyo
AU - Miyao, Mitsue
AU - Murata, Norio
N1 - Funding Information:
The authors are grateful to Ms. Y. Fujimura and Ms. H. Kajiura, National Institute for Basic Biology, for isolation of the 18-kDa protein and its 17-kDa fragment, and also determination of partial amino acid sequences with their skilled techniques. This work was supported by Grants-in-Aid for Cooperative Research (58340037 and 60304093) to T.K. and N.M. from the Ministry of Education, Science and Culture of Japan.
PY - 1986/6/10
Y1 - 1986/6/10
N2 - When the NaCl extract from spinach Photosystem II particles was dialyzed against a low-salt medium, the 18-kDa protein slowly degraded to a fragment of 17 kDa. This observation suggests that a proteinase previously associated with the Photosystem II particles in a latent form was activated by dissociation with NaCl. The 18-kDa protein and the 17-kDa fragment were purified, and their N-terminal amino acid sequences and total amino acid compositions were determined. These results determined 44 amino acid residues at the N-terminal of the 18-kDa protein, and suggest that 12 amino acid residues (mostly hydrophobic) at the N-terminal were lost by the degradation. The 18-kDa protein could rebind to the NaCl-treated and 24-kDa protein-supplemented Photosystem II particles and sustain their oxygen-evolution activity in a low-Cl- medium, whereas the 17-kDa fragment had lost these abilities. These observations suggest that the N-terminal region of the 18-kDa protein forms a domain which binds to Photosystem II particles.
AB - When the NaCl extract from spinach Photosystem II particles was dialyzed against a low-salt medium, the 18-kDa protein slowly degraded to a fragment of 17 kDa. This observation suggests that a proteinase previously associated with the Photosystem II particles in a latent form was activated by dissociation with NaCl. The 18-kDa protein and the 17-kDa fragment were purified, and their N-terminal amino acid sequences and total amino acid compositions were determined. These results determined 44 amino acid residues at the N-terminal of the 18-kDa protein, and suggest that 12 amino acid residues (mostly hydrophobic) at the N-terminal were lost by the degradation. The 18-kDa protein could rebind to the NaCl-treated and 24-kDa protein-supplemented Photosystem II particles and sustain their oxygen-evolution activity in a low-Cl- medium, whereas the 17-kDa fragment had lost these abilities. These observations suggest that the N-terminal region of the 18-kDa protein forms a domain which binds to Photosystem II particles.
KW - (Spinach)
KW - Chloride effect
KW - Oxygen evolution
KW - Proteinase
KW - Thylakoid protein
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U2 - 10.1016/0005-2728(86)90019-8
DO - 10.1016/0005-2728(86)90019-8
M3 - Article
AN - SCOPUS:0001628742
VL - 850
SP - 146
EP - 155
JO - Biochimica et Biophysica Acta - Bioenergetics
JF - Biochimica et Biophysica Acta - Bioenergetics
SN - 0005-2728
IS - 1
ER -