Influence of pH, Mg2+, and lipid composition on the aggregation state of the diatom FCP in comparison to the LHCII of vascular plants
Influence of pH, Mg2+, and lipid composition on the aggregation state of the diatom FCP in comparison to the LHCII of vascular plants
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DOI：
10.1007/s11120-013-9951-x
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发表时间：
2014-03-01
影响因子：
3.7
通讯作者：
Goss, Reimund
中科院分区：
文献类型：
--
作者：
Schaller, Susann;Richter, Konstantin;Goss, Reimund
在本研究中，Mg 2+离子和低pH值的硅藻FCP和LHCII的维管植物的聚集状态的影响进行了研究。此外，与复合物的类囊体膜脂的浓度进行了测定。结果表明，FCP，其中含有一个显着较高浓度的带负电荷的脂质SQDG和PG，是不太敏感的Mg2+和低pH值比LHCII，其特征在于较低的量的SQDG和较高浓度的MGDG。高MgCl2浓度和pH值低于pH 6诱导的LHCII的吸收和77K荧光发射光谱的显着变化，表明捕光复合物的强聚集。在蔗糖垫上离心后，这种聚集也可见为团块。虽然FCP响应的吸收和荧光光谱的变化，以低pH值和Mg 2+孵育，这些光谱的变化是不太明显的比LHCII所观察到的。此外，FCP复合物在与低pH值或高Mg 2+浓度孵育后未显示可见的沉淀。只有Mg 2+和pH 5的联合作用导致FCP聚集体的大小可以通过离心沉淀。FCP聚集Mg 2+和低pH值的敏感性降低进行了讨论相对于周围的FCP和LHCII和硅藻和维管植物的不同类囊体膜组织的脂质浓度的差异。
In the present study, the influence of Mg2+ ions and low pH values on the aggregation state of the diatom FCP and the LHCII of vascular plants was studied. In addition, the concentration of thylakoid membrane lipids associated with the complexes was determined. The results demonstrate that the FCP, which contained a significantly higher concentration of the negatively charged lipids SQDG and PG, was less sensitive to Mg2+ and low pH values than the LHCII which was characterized by lower amounts of SQDG and a higher concentration of MGDG. High MgCl2 concentrations and pH values below pH 6 induced significant changes of the absorption and 77K fluorescence emission spectra of the LHCII, indicating a strong aggregation of the light-harvesting complex. This aggregation was also visible as a pellet after centrifugation on a sucrose cushion. Although the FCP responded with changes of the absorption and fluorescence spectra to low pH and Mg2+ incubation, these spectral changes were less pronounced than those observed for the LHCII. In addition, the FCP complexes did not show a visible pellet after incubation with either low pH values or high Mg2+ concentrations. Only the combined action of Mg2+ and pH 5 led to FCP aggregates of a size that could be pelleted by centrifugation. The decreased sensitivity of FCP aggregation to Mg2+ and low pH is discussed with respect to the differences in the concentration of the lipids surrounding the FCP and LHCII and the different thylakoid membrane organizations of diatoms and vascular plants.