Studies on the structure and function of photosystem I reaction center complex

1992 Fiscal Year Final Research Report Summary

• Project/Area Number: 03640567
• Research Category: Grant-in-Aid for General Scientific Research (C)
• Allocation Type: Single-year Grants
• Research Field: 植物生理学
• Research Institution: Kanazawa University
• Principal Investigator: HOSHINA Satoshi Kanazawa University, Faculty of Science Research Associate, 理学部, 助手 (50019486)
• Project Period (FY): 1991 – 1992
• Keywords: Cross-linking / Iron-sulfur center / P700 / Photoinhibition / Photosystem I / Polypeptide / Reaction center / Trypsin

Research Abstract

1. Photosystem I particles (PSI-200) prepared by the solubilization of spinach thylakoids with Triton X-100 have been treated with a cross-linker, dithiobis(succinimidylpropionate) (DSP) which reacts specifically with amino groups. The cross-linking with DSP is concluded to give a simple method for stabilization of the iron-sulfur centers A and B in PSI-200.
2. Irradiation of PSI-200 with high intensity of white light caused a decrease of the electron transport activity from DCIPH_2 to methylviologen and an irreversible bleaching of chlorophyll. The content of P700 was not affected by this treatment. No photoinhibition was, however, shown in PSI complex (Chl/P700 = 40) which was prepared by the solubilization of PSI-200 with Triton X-100, followed by column chromatography on hydroxyl-apatite gel. The column chromatography may give the simple method of PSI preparation for studies on the primary photochemistry.
3. PSI reaction center complex was prepared by the heat-treatment of PSI-200 in the presence of ethylene glycol. The complex was mainly composed with three proteins, PSI-A, PSI-B and PSI-K. The trypsin-treatment of the complex reconstituted into liposomes resulted in the formation of three chlorophyll-protein bands with smaller molecular weight than that of the reaction center complex. Two of them contained P700 and A_1. Characterization of the bands thus obtained is now under investigation.

Research Products

• [Publications] Watanabe,S.,Tamai,N.,Hoshina,S.,Sanada,Y.,Nishida,K.and Wada,K.: "The respiration dependent malate accumulation in lcaves of a crassulaccan acid mctabolism plant,Kalanchoe daigremontiana Hamet et Perr." J.Plant Physiol.140. 129-133 (1992)
  • Description: 「研究成果報告書概要(和文)」より
• [Publications] Hoshina,S.,Sue,S.,Wada,K.,Enami,I.and Itoh,S.: "Stabilization of iron-sulfur centers A and B in photosystcm by chcmical cross-linking." Research in Photosynthesis(ed.N.Murata). (1993)
  • Description: 「研究成果報告書概要(和文)」より
• [Publications] Hoshina,S.and Itoh,S.: "Photosystem I reaction center in oxygenic photosynthetic organisms:Current vicws and future.in Photosynthesis:Photorcactions to Plant Productivity" Oxford & IBH Publishing Co.(eds.,Y.P.Abrol,P.Mohanty and Govindjee), 32 (1993)
  • Description: 「研究成果報告書概要(和文)」より
• [Publications] Watanabe,S., Tamai,N., Hoshina,S., Sanada,Y., Nishida,K. and Wada,K.: "The respiration dependent malate accumulation in leaves of a crassulacean acid metabolism plant, Kalanchoe daigremontiana Hamet et Perr." J. Plant Physiol.140. 129-133 (1992)
  • Description: 「研究成果報告書概要(欧文)」より
• [Publications] Hoshina,S., Sue,S., Wada,K., Enami,I. and Itoh,S.: "Stabilization of iron-sulfur centers A and B in photosystem I particles by chemical cross-linking." Research in Photosynthesis (ed. N.Murata). (1993)
  • Description: 「研究成果報告書概要(欧文)」より
• [Publications] Hoshina,S. and Itoh,S.: "Photosystem I reaction center in oxygenic photosynthetic organisms: Current views and the future. in Photosynthesis: Photoreactions to Plant Productivity." Oxford & IBH Publishing Co. (eds. Y.P.Abrol, P.Mohanty and Govindjee). 51-82 (1993)
  • Description: 「研究成果報告書概要(欧文)」より