Structure and function of the PsbP protein of Photosystem II from higher plants
Structure and function of the PsbP protein of Photosystem II from higher plants
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DOI：
10.1007/s11120-004-7160-3
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发表时间：
2005-06-01
影响因子：
3.7
通讯作者：
Sato, F
中科院分区：
文献类型：
--
作者：
Ifuku, K;Nakatsu, T;Sato, F
PsbP是光系统II（PS II）的一个膜外亚基，参与了水裂解反应中的Ca ~（2+）和Cl ~-的截留。在本研究中，我们重新调查的N-末端区域的PsbP的三维结构的基础上的作用。在先前的论文[Ifuku和Sato（2002）Plant Cell Physiol 43：1244-1249]中，发现缺少19个N-末端残基的截短的PsbP（Delta 19）结合到缺少PsbP和PsbQ的NaCl洗涤的PS II，而根本没有氧释放的活化。PsbP的三维（3D）结构表明，缺失19个N-末端残基将使其蛋白质结构不稳定，如Delta 19对胰蛋白酶消化的高敏感性所示。因此，产生了缺失15个N-末端残基的截短的PsbP（Delta 15），其保留了核心PsbP结构。而德尔塔15是抵抗胰蛋白酶消化和结合NaCl洗涤PS II膜，它没有显示出激活的氧释放。这一结果表明，PsbP的N-端15个柔性区与PS Ⅱ的相互作用对PS Ⅱ中Ca ~（2+）和Cl ~-的滞留起着重要作用，而N-端15个残基对PsbP与PS Ⅱ的结合不是必需的。可能的N-末端残基的PsbP，将参与这种相互作用进行了讨论。
PsbP is a membrane extrinsic subunit of Photosystem II (PS II), which is involved in retaining Ca2+ and Cl-, two inorganic cofactors for the water-splitting reaction. In this study, we re-investigated the role of N-terminal region of PsbP on the basis of its three-dimensional structure. In previous paper [Ifuku and Sato (2002) Plant Cell Physiol 43: 1244-1249], a truncated PsbP lacking 19 N-terminal residues (Delta 19) was found to bind to NaCl-washed PS II lacking PsbP and PsbQ without activation of oxygen evolution at all. Three-dimensional (3D) structure of PsbP suggests that deletion of 19 N-terminal residues would destabilize its protein structure, as indicated by the high sensitivity of Delta 19 to trypsin digestion. Thus, a truncated PsbP lacking 15 N-terminal residues (Delta 15), which retained core PsbP structure, was produced. Whereas Delta 15 was resistant to trypsin digestion and bound to NaCl-washed PS II membranes, it did not show the activation of oxygen evolution. This result indicated that the interaction of 15-residue N-terminal flexible region of PsbP with PS II was important for Ca2+ and Cl- retention in PS II, although the N-15-terminal residues were not essential for the binding of PsbP to PS II. The possible N-terminal residues of PsbP that would be involved in this interaction are discussed.