Subunit composition and pigmentation of fucoxanthin-chlorophyll proteins in diatoms:: Evidence for a subunit involved in diadinoxanthin and diatoxanthin binding
Subunit composition and pigmentation of fucoxanthin-chlorophyll proteins in diatoms:: Evidence for a subunit involved in diadinoxanthin and diatoxanthin binding
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DOI：
10.1021/bi061249h
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发表时间：
2006-10-31
期刊：
影响因子：
2.9
通讯作者：
Buechel, Claudia
中科院分区：
文献类型：
--
作者：
Beer, Anja;Gundermann, Kathi;Buechel, Claudia
从中心硅藻meneghiniana中纯化了两种不同的岩藻黄素-叶绿素蛋白复合物（FCP），并对其多肽和色素组成进行了表征。低聚FCPb复合体最有可能由fcp5基因产物组成，而三聚FCPa具有由fcp1-3和fcp6/7编码的亚基。当FCPa从HL条件下生长的藻类中分离出来时，后者多肽的数量增加。Fcp6/7多肽的增加伴随着叶黄素循环色素池的增加，二英黄质和硅藻黄质，以及岩藻黄质含量的减少。此外，去环氧化比率，即与叶黄素循环色素池相关的硅黄素的量增加了2倍。在荧光产率方面，与LL FCPa相比，HL FCPa被猝灭。这与大量的硅黄素结合是一致的，硅黄素被认为是像高等植物中的玉米黄质一样的猝灭剂。因此，我们得出结论，FCPa中硅藻黄素含量的增加具有保护作用，与此同时，由于硅藻黄素含量的减少，光捕获功能减弱。
Two different fucoxanthin-chlorophyll protein complexes ( FCP) were purified from the centric diatom Cyclotella meneghiniana and characterized with regard to their polypeptide and pigment composition. Whereas the oligomeric FCPb complex is most probably composed of fcp5 gene products, the trimeric FCPa has subunits encoded by fcp1-3 and fcp6/7. The amount of the latter polypeptide is enhanced when FCPa is isolated from algae grown under HL conditions. This increase in Fcp6/7 polypeptides is accompanied by an increase in the pool of xanthophyll cycle pigments, diadinoxanthin and diatoxanthin, and a concomitant decrease in fucoxanthin content. In addition, the de-epoxidation ratio, i.e., the amount of diatoxanthin in relation to the pool of xanthophyll cycle pigments, is increased by a factor of 2. With regard to fluorescence yield, HL FCPa was quenched in comparison to LL FCPa. This is in accordance with the larger amount of diatoxanthin that is bound, which is supposed to act as a quencher like zeaxanthin in higher plants. Thus, we conclude that the enhanced content of diatoxanthin in FCPa plays a protective role, which is paralleled by a weakened light harvesting function due to a smaller amount of fucoxanthin.