• Search Research Projects
  • Search Researchers
  • How to Use
  1. Back to project page

1987 Fiscal Year Final Research Report Summary

Analysis of spinach photosystem-I reaction-center complex by dissociation and re-association of its components

Research Project

Project/Area Number 61540493
Research Category

Grant-in-Aid for General Scientific Research (C)

Allocation TypeSingle-year Grants
Research Field 植物生理学
Research InstitutionTEIKYO UNIVERSITY

Principal Investigator

IKEGAMI Isamu  Fac.Pharmaceutical Sci., Teikyo Univ., 薬学部, 助教授 (10082322)

Project Period (FY) 1986 – 1987
KeywordsPhotosynthesis / Phtosystem I / Reaction center / P700 / vitamin K_1
Research Abstract

1. Ether treatment of PS-I particle removed all the vitamin K-1 (2.2 mol/P700 in the original particles) as well as most antenna pigments which led a chl-a/P700 ratio to less than 10 in the particle. 2. This preparation showed the A_o^- EPR signal but no A^1 signal even after long illumination at 210K to 230K. 3. Flash-induced absorption changes were studied in this prepartion, where the initial absorption change at 820 nm was followed by a fast decay(t_<1/2>-47 ns at 278K and -82 ns at 10K) which is attributed to the decay of the primary radical pair(P700^+-A^o^-). 4. The A_o^-/A_- spectrum was obtained by the subtraction of the P700^+/P700 pair(P^+/A^-). It includes bleachings centered at 690 and 430 nm, and broad positive bands in the near infra-red and the blue-green. This spectrum is consistent with A_o being chl-a absorbing at 690 nm. 5. A slower phase of the absorption decay is attributed to the P700 triplet dacay, which was formed as a result of the biradical recombination, with a yield of about 30% at 278K and about 75% at 10K. 6. Addition of vitamin K-1 to the particle resulted in a decrease in the amplitude of the fast nanosecond decay and a concomitant increase in the amplitude of a slow phase, indicating an efficient electron transfer from A_0- to vitamin K-1. 7. However, the photoreduction of Fe-S centers(F_X, F_A and F_B ) was still observed even in the absence of vitamin K-1 when we used the continuous illumination as the excitation light, suggesting the by-pass electron flow from A_0 to A_2(X), through which electrons can gradually accumulate on Fe-S centers during prolonded illumination.

  • Research Products

    (11 results)

All Other

All Publications (11 results)

  • [Publications] Iton shigeru: Biochim.Biophys.Acta. 893. 508-516 (1987)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] Ikegami Isamu: Biochim.Biophys.Acta. 893. 517-523 (1987)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] Setif Pierre: Biochim.Biophys.Acta. 894. 146-156 (1987)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] Ikegami Isamu: Biochim.Biophys.Acta. 894. 414-422 (1987)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] Mathis Paul: Photosynthesis Research. in press (1988)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] Ikegami Isamu: Biochim.Biophys.Acta. in press (1988)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] Itoh Shigeru, Iwaki Masayo and Ikegami Isamu: "Extraction of vitamin K-1 from photosystem I particles by treatment with diethyle ether and its effects on the A_1- EPR signal and system I photochemistry" Biochim. Biophys. Acta. 893. 508-516 (1987)

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] Ikegami Isamu and Itoh Shigeru: "Evidence for the interaction of the photosystem I secondary electron acceptor X with chlorophyll a in spinach photosystem I particles" Biochim. Biophys. Acta. 893. 517-523 (1987)

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] Setif Pierre, Ikegami Isamu and Biggins John: "Light-induced charge separation in photosystem I at low temperature is not influenced by vitamin K-1" Biochim. Biophys. Acta. 894. 146-156 (1987)

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] Ikegami Isamu, Setif Pierre and Mathis Paul: "Absorption studies of photosystem I photochemistry in the absence of vitamin K-1" Biochim. Biophys. Acta. 894. 414-422 (1987)

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] Mathis Paul, Ikegami Isamu and Setif Pierre: "Nanosecond flash studies of the absorption spectrum of the photosystem I primary acceptor A_0" Photosynthesis Research. in press (1988)

    • Description
      「研究成果報告書概要(欧文)」より

URL: 

Published: 1989-03-30  

Information User Guide FAQ News Terms of Use Attribution of KAKENHI

Powered by NII kakenhi