Identification of several sub-populations in the pool of light harvesting proteins in the pennate diatom Phaeodactylum tricornutum
Identification of several sub-populations in the pool of light harvesting proteins in the pennate diatom Phaeodactylum tricornutum
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DOI：
10.1016/j.bbabio.2012.10.017
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发表时间：
2013-03-01
影响因子：
4.3
通讯作者：
Buechel, Claudia
中科院分区：
文献类型：
--
作者：
Gundermann, Kathi;Schmidt, Matthias;Buechel, Claudia
硅藻是海洋浮游植物光合作用生产力的主要贡献者。在这些生物中，岩藻黄质-叶绿素蛋白(FCP)作为捕光蛋白。我们研究了三角褐指藻在弱光和强光条件下的FCP复合体。对主要的FCP池进行细分，得到不同的三聚体复合体。在三聚体中仅发现Lhcf和LHC样蛋白。在L1下，第一个多肽部分含有6个不同的Lhcf，主要由Lhcf10组成。它的特点是岩藻黄质(FX)含量最高。第二类以Lhcf10、Lhcf5和Lhcf2为主，Fx/Chl c比值较低。少量的Fx/Chl c也是最丰富的FCP络合物的特征，在组分3中发现，主要由Lhcf5组成。这些FCP结合的FX分子具有最强的红移。最后两个组分包含主要由Lhcf4构建的FCP络合物，含有更多在较短波长吸收的FX分子。在HI下，不同组分得到相同的主要多肽，光谱特征几乎相同，但Diadinoxantin含量较高。在HI下，Lhcf5的总量减少，而最后两个组分的数量增加，从而增加了Lhcf4的数量。在不同的HL组分中均检测到Lhcfl1，但在HL组分中均未检测到LHcfl1，而仅在HL组分中发现了两个新的LHC样蛋白。这是首次报道羽状硅藻中不同的三聚体FCP复合体，它们的多肽组成和着色力不同，并且在光下有差异表达。(C)2012爱思唯尔B.V.保留所有权利。
Diatoms are major contributors to the photosynthetic productivity of marine phytoplankton. In these organisms, fucoxanthin-chlorophyll proteins (FCPs) serve as light-harvesting proteins. We have explored the FCP complexes in Phaeodactylum tricornutum under low light (LL) and high light (HL) conditions. Sub-fractionating the pool of major FCPs yielded different populations of trimeric complexes. Only Lhcf and Lhc-like proteins were found in the trimers. Under LL, the first polypeptide fraction contained six different Lhcfs and was mainly composed of Lhcf10. It was characterised by the highest amount of fucoxanthin (Fx). The second was dominated by Lhcf10, Lhcf5 and Lhcf2, and had a lower Fx/Chl c ratio. Little Fx/Chl c also characterised the most abundant FCP complexes, found in fraction 3, composed mainly of Lhcf5. These FCPs bound Fx molecules with the strongest bathochromic shift. The last two fractions contained FCP complexes that were built mainly of Lhcf4, harbouring more Fx molecules that absorbed at shorter wavelengths. Under HI, the same main polypeptides were retrieved in the different fractions and spectroscopic features were almost identical except for a higher diadinoxanthin content. The total amount of Lhcf5 was reduced under HI, whereas the amount of the last two fractions and thereby Lhcf4 was increased. Lhcfl1 was identified in different LL fractions, but not detected in any HL fraction, while two new Lhc-like proteins were only found under HL This is the first report on different trimeric FCP complexes in pennate diatoms, which differ in polypeptide composition and pigmentation, and are differentially expressed by light. (C) 2012 Elsevier B.V. All rights reserved.