Does the Reconstitution of RC-LH1 Complexes from Rhodopseudomonas acidophila Strain 10050 into a Phospholipid Bilayer Yield the Optimum Environment for Optical Spectroscopy?
Does the Reconstitution of RC-LH1 Complexes from Rhodopseudomonas acidophila Strain 10050 into a Phospholipid Bilayer Yield the Optimum Environment for Optical Spectroscopy?
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DOI：
10.1021/jp409980k
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发表时间：
2013-12-05
影响因子：
3.3
通讯作者：
Koehler, Juergen
中科院分区：
文献类型：
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作者：
Boehm, Paul S.;Kunz, Ralf;Koehler, Juergen
我们研究了红球藻（Rhodopropylidene，Rps）的反应中心捕光1（RC-LH 1）复合物。嗜酸乳杆菌在洗涤剂缓冲液中的溶解并重构成磷脂双层，并将结果与对固定在聚乙烯醇（PVA）中的RC-LH 1进行的早期研究的结果进行比较。本研究的目的是测试在PVA基质中的复合物的固定化是否可能导致蛋白质的劣化，从而限制可从光谱学获得的可访问信息。已经发现，溶解在去污剂缓冲溶液中的复合物受到快速光谱动力学的影响，从而阻止了单分子光谱学的任何有意义的应用。相比之下，对于双层样品，它揭示了重构过程导致相对于在PVA膜中制备复合物的破碎复合物的显著更大的分数。此外，我们发现，对于完整的复合物的关键光谱特征，如光谱分离的频带和它们的过渡偶极矩的相互取向的统计，显示没有变化依赖于使用双层或PVA作为矩阵。考虑到在重建过程中所涉及的额外努力，完整的RC-LH 1复合物的量较低，并且关于决定性的光谱细节，相对于将复合物嵌入PVA基质中的相同结果，我们得出结论，将这些蛋白质固定在PVA基质中是对单个捕光复合物进行低温实验的良好选择。
We have investigated reaction-center light-harvesting 1 (RC-LH1) complexes from Rhodopseudomonas (Rps.) acidophila in detergent buffer solution and reconstituted into a phospholipid bilayer and compared the results with the outcome of an earlier study conducted on RC-LH1 immobilized in polyvinyl alcohol (PVA). The aim of this study was to test whether the immobilization of the complexes in a PVA matrix might lead to a deterioration of the proteins and thereby limit the accessible information that can be obtained from optical spectroscopy. It has been found that the complexes dissolved in a detergent buffer solution are subject to fast spectral dynamics preventing any meaningful application of single-molecule spectroscopy. In contrast, for the bilayer samples it is revealed that the reconstitution process results in a significantly larger fraction of broken complexes with respect to the preparation of the complexes in a PVA film. Moreover, we find that for the intact complexes the statistics of the key spectral features, such as the spectral separations of the bands and the mutual orientation of their transition-dipole moments, show no variation dependent on using either a bilayer or PVA as a matrix. Given the additional effort involved in the reconstitution process, the lower amount of intact RC-LH1 complexes and, concerning the decisive spectral details, the identical results with respect to embedding the complexes in a PVA matrix, we come to the conclusion that the immobilization of these proteins in a PVA matrix is a good choice for conducting low-temperature experiments on individual light-harvesting complexes.