PsbU, a Protein Associated with Photosystem II, Is Required for the Acquisition of Cellular Thermotolerance in<i>Synechococcus</i> species PCC 70021

  • Yoshitaka Nishiyama
    Department of Regulation Biology, National Institute for Basic Biology, Myodaiji, Okazaki 444–8585, Japan (Y.N., D.A.L., N.M.)
  • Dmitry A. Los
    Department of Regulation Biology, National Institute for Basic Biology, Myodaiji, Okazaki 444–8585, Japan (Y.N., D.A.L., N.M.)
  • Norio Murata
    Department of Regulation Biology, National Institute for Basic Biology, Myodaiji, Okazaki 444–8585, Japan (Y.N., D.A.L., N.M.)

抄録

<jats:title>Abstract</jats:title> <jats:p>PsbU is an extrinsic protein of the photosystem II complex of cyanobacteria and red algae. Our previous in vitro studies (Y. Nishiyama, D.A. Los, H. Hayashi, N. Murata [1997] Plant Physiol 115: 1473–1480) revealed that PsbU stabilizes the oxygen-evolving machinery of the photosystem II complex against heat-induced inactivation in the cyanobacteriumSynechococcus sp. PCC 7002. To elucidate the role of PsbU in vivo, we inactivated the psbU gene inSynechococcus sp. PCC 7002 by targeted mutagenesis. Inactivation of the psbU gene resulted in marked changes in the acclimative responses of cells to high temperature: Mutated cells were unable to increase the thermal stability of their oxygen-evolving machinery when grown at moderately high temperatures. Moreover, the cellular thermotolerance of the mutated cells failed to increase upon acclimation of cells to high temperature. The heat-shock response, as assessed in terms of the levels of homologs of the heat-shock proteins Hsp60, Hsp70, and Hsp17, was unaffected by the mutation in psbU, suggesting that heat-shock proteins were not involved in the changes in the acclimative responses. Our observations indicate that PsbU is involved in the mechanism that underlies the enhancement of the thermal stability of the oxygen-evolving machinery and that the stabilization of the oxygen-evolving machinery is crucial for the acquisition of cellular thermotolerance.</jats:p>

収録刊行物

  • Plant Physiology

    Plant Physiology 120 (1), 301-308, 1999-05-01

    Oxford University Press (OUP)

被引用文献 (6)*注記

もっと見る

詳細情報

問題の指摘

ページトップへ