Department of Plant Sciences, University of Western Ontario, London, Canada N6A 5B7.
Plant Physiol. 1992 Jul;99(3):830-6. doi: 10.1104/pp.99.3.830.
A survey of isolated thylakoids from 11 different higher plant species (Spinacia oleracea L., Pisum sativum L., Vicia faba L., Brassica napus L., Vigna sinensis L., Vinca minor L., Secale cereale L., Triticum aestivum L., Triticosecale Wittn., Hordeum vulgare L., Zea mays L.) indicated that the ratio of the oligomeric:monomeric form of the light-harvesting complex II was twofold higher for the dicots (3.16 +/- 0.35) than the monocots (1.64 +/- 0.25) examined under identical separation procedures. Under conditions specifically designed to stabilize the oligomeric form in vitro, we show that the oligomeric form of dicot light-harvesting complex II is twice as stable to solubilization in the presence of sodium dodecyl sulfate (SDS) than that observed for monocots. This decreased stability of monocot light-harvesting complex II is associated with a twofold increase in the trienoic fatty acid level of thylakoid phosphatidylglycerol but with no significant changes in the trienoic fatty acid levels in the major galactolipids. In addition, SDS polyacrylamide gel electrophoresis and western blot analyses with monoclonal antibodies indicated that monocots exhibited greater heterogeneity in the polypeptide complements associated with subfractions of light-harvesting complex II than the dicots examined. The data indicate that the oligomeric form of the light-harvesting complex II is not the result of a simple oligomerization of a common monomeric unit. We suggest that the difference in stability of the oligomeric form of light-harvesting complex II in isolated thylakoids of monocots and dicots is probably due to a differential accessibility to SDS. The differential SDS accessibility may be due to differences in thylakoid protein-protein and/or protein-lipid interactions.
对 11 种不同高等植物（菠菜、豌豆、蚕豆、油菜、豇豆、长春花、黑麦、小麦、小麦属、大麦、玉米）的分离类囊体的调查表明，二倍体植物（3.16 +/- 0.35）的寡聚体：单体形式的光捕获复合物 II 的比例是单子叶植物（1.64 +/- 0.25）的两倍，在相同的分离程序下进行检查。在专门设计的条件下，我们在体外稳定寡聚体形式，表明二倍体光捕获复合物 II 的寡聚体形式在存在十二烷基硫酸钠（SDS）时比观察到的单子叶植物稳定两倍。单子叶植物光捕获复合物 II 的这种稳定性降低与类囊体磷脂酰甘油中三烯脂肪酸水平增加两倍有关，但主要半乳糖脂中的三烯脂肪酸水平没有显著变化。此外，SDS 聚丙烯酰胺凝胶电泳和用单克隆抗体进行的 western blot 分析表明，与二倍体相比，单子叶植物的光捕获复合物 II 亚组分相关的多肽补体表现出更大的异质性。数据表明，光捕获复合物 II 的寡聚体形式不是常见单体单元简单寡聚化的结果。我们认为，单子叶植物和二倍体分离类囊体中光捕获复合物 II 寡聚体形式稳定性的差异可能是由于 SDS 可及性的差异。SDS 可及性的差异可能是由于类囊体蛋白-蛋白和/或蛋白-脂质相互作用的差异所致。
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