Inactivation and Calcium-Dependent Reactivation of Oxygen Evolution in Photosystem II Preparations Treated at pH 3.0 or with High Concentrations of NaCl :

NDLデジタルコレクション 被引用文献1件
  • Shen,Jian-Ren
    Department of Biology, Faculty of Science, University of Tokyo:(Present)Solar Energy Research Group, The Institute of Physical and Chemical Research (RIKEN)
  • Katoh,Sakae
    Department of Biology, Faculty of Science, University of Tokyo

この論文をさがす

抄録

A brief treatment at pH 3.0 of Photosystem II (PS II) membranes containing two bound Ca^<2+> from rice resulted in strong suppression of oxygen evolution concomiiant with extraction of one Ca^<2+> and the lost activity was restored on addition of 50 mM Ca^<2+>. However, inactivation of oxygen evolution by low pH-treatment of oxygen-evolving PS II complexes containing only one Ca^<2+> from a rice chlorophyll b-deficient mutant was not associated with extraction of the bound Ca^<2+>, although oxygen evolution was markedly enhanced by the addition of Ca^<2+> to the treated complexes. Thus, the acid-inactivation of oxygen evolution cannot be related to extraction of Ca^<2+>. On the other hand, low pH-treatment was found to share the following common features with NaCl-treatment which also causes a Ca^<2+>-reversible inactivation of oxygen evolution. (1) Exposure of PS II membranes to pH 3.0 resulted in solubilization of the 23 and 17 kDa extrinsic proteins, although the released proteins rebound to the membranes when pH was raised to 6.5. (2) There was an apparent heterogeneity in the binding affinity of Ca^<2+> effective in restoration of the oxygen-evolving activity. (3) Low pH-treated preparations required a higher concentration of Ca^<2+> for the maximum reactivation of oxygen evolution than did NaCl-washed preparations. This was also the case with Sr^<2+>, which stimulated oxygen evolution of both low pH-treated and NaCl-washed PS II membranes to smaller extents. When the extrinsic 23 and 17 kDa proteins had been removed, however, Ca^<2+> concentration dependence of oxygen evolution in low pH-treated membranes became similar to that in NaCl-washed PS 11 preparations and the changes were largely reversed by rebinding of the two proteins. These results strongly suggest that low pH-treatment and NaCl-wash involve similar mechanisms of Ca^<2+>-dependent reactiv ation.

収録刊行物

被引用文献 (1)*注記

もっと見る

キーワード

詳細情報 詳細情報について

問題の指摘

ページトップへ