The light-harvesting antenna of the diatom Phaeodactylum tricornutum -: Evidence for a diadinoxanthin-binding subcomplex
The light-harvesting antenna of the diatom Phaeodactylum tricornutum -: Evidence for a diadinoxanthin-binding subcomplex
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DOI：
10.1111/j.1742-4658.2005.04846.x
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发表时间：
2005-09-01
期刊：
影响因子：
5.4
通讯作者：
Ruban, AV
中科院分区：
文献类型：
--
作者：
Guglielmi, G;Lavaud, J;Ruban, AV
硅藻与高等植物的不同之处在于它们的触角系统，在多肽和色素含量方面。设计了一种快速分离硅藻三角褐指藻（Phaeodactylum tricornutum）膜内捕光复合物（LHC）的方法，以确定是否存在不同的LHC亚复合物，以及确定它们之间色素和多肽的不均匀分布。分离出两种不同的级分，其含有功能性低聚复合物。主要和更稳定的复合物（约占总多肽的75%）携带大部分叶绿素a，几乎只有一种类型的类胡萝卜素，岩藻黄素。小复合体，携带约10-15%的总天线叶绿素和只有少量的叶绿素c，是高度富集的硅甲藻黄素，主要的叶黄素循环类胡萝卜素。这两种复合物的多肽组成也不同，表明天线内的专门功能。富含硅藻黄质的复合物可能是硅藻黄质脱环氧化成硅藻黄质的主要发生之处。
Diatoms differ from higher plants by their antenna system, in terms of both polypeptide and pigment contents. A rapid isolation procedure was designed for the membrane-intrinsic light harvesting complexes (LHC) of the diatom Phaeodactylum tricornutum to establish whether different LHC subcomplexes exist, as well to determine an uneven distribution between them of pigments and polypeptides. Two distinct fractions were separated that contain functional oligomeric complexes. The major and more stable complex (approximate to 75% of total polypeptides) carries most of the chlorophyll a, and almost only one type of carotenoid, fucoxanthin. The minor complex, carrying approximate to 10-15% of the total antenna chlorophyll and only a little chlorophyll c, is highly enriched in diadinoxanthin, the main xanthophyll cycle carotenoid. The two complexes also differ in their polypeptide composition, suggesting specialized functions within the antenna. The diadinoxanthin-enriched complex could be where the de-epoxidation of diadinoxanthin into diatoxanthin mostly occurs.