Light-harvesting Chlorophyll a/b-binding Protein Stably Inserts into Etioplast Membranes Supplemented with Zn-pheophytina/b *
Light-harvesting Chlorophyll a/b-binding Protein Stably Inserts into Etioplast Membranes Supplemented with Zn-pheophytina/b *
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光捕获叶绿素 a/b 结合蛋白稳定插入补充有 Zn-脱镁叶绿素 /b 的 Etioplast 膜 *
DOI：
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发表时间：
1997
影响因子：
4.8
通讯作者：
H. Paulsen
中科院分区：
文献类型：
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作者：
A. Kuttkat;I. Edhofer;L. Eichacker;H. Paulsen
光能叶绿素/b结合蛋白（LHCP）或其前体pLHCP在体外不能稳定插入大麦黄质膜。然而，当这些黄体膜补充叶绿素类似物Zn-pheophytin a/b（由Zn-pheophytin a/b和焦磷酸二菊酯原位合成）时，pLHCP插入到蛋白酶抗性状态。这证明叶绿素是黄质膜中唯一缺乏稳定LHCP插入所必需的成分。单独合成Zn-pheophytin b可以促进LHCP在体外插入到蛋白酶抗性状态，而单独合成Zn-pheophytin a则不会。在膜上添加叶绿素a和叶绿素b也可以刺激pLHCP插入到黄体膜中，尽管与原位合成的锌-叶绿素a/b相比，其效率显着降低。将pLHCP插入到叶绿素-或锌-叶绿素-补充的黄体膜中，然后用蛋白酶测定，只发现了指示单体主要光收集叶绿素a/b复合物（LHCII）的蛋白酶消化产物，而没有指示三聚体复合物的蛋白酶消化产物。在这方面，叶绿素或锌-叶绿素补充的黄体膜类似于绿化早期的类囊体膜：绿大麦质体膜中插入的pLHCP在绿化超过1小时后才组装成三聚体LHCII。
Light-harvesting chlorophylla/b-binding protein, LHCP, or its precursor, pLHCP, cannot be stably inserted into barley etioplast membranes in vitro. However, when these etioplast membranes are supplemented with the chlorophyll analogs Zn-pheophytin a/b, synthesizedin situ from Zn-pheophorbide a/b and digeranyl pyrophosphate, pLHCP is inserted into a protease-resistant state. This proves that chlorophyll is the only component lacking in etioplast membranes that is necessary for stable LHCP insertion. Synthesis of Zn-pheophytin b alone promotes insertion of LHCP in vitro into a protease-resistant state, whereas synthesis of Zn-pheophytin a alone does not. Insertion of pLHCP into etioplast membranes can also be stimulated by adding chlorophyll a and chlorophyll b to the membranes, albeit at a significantly lower efficiency as compared with Zn-pheophytin a/b synthesized in situ. When pLHCP is inserted into chlorophyll- or Zn-pheophytin-supplemented etioplast membranes and then assayed with protease, only the protease digestion product indicative of the monomeric major light-harvesting chlorophyll a/b complex (LHCII) is found but not the one indicating trimeric complexes. In this respect, chlorophyll- or Zn-pheophytin-supplemented etioplast membranes resemble thylakoid membranes at an early greening stage: pLHCP inserted into plastid membranes from greening barley is assembled into trimeric LHCII only after more than 1 h of greening.