Single-molecule spectroscopic characterization of light-harvesting 2 complexes reconstituted into model membranes
Single-molecule spectroscopic characterization of light-harvesting 2 complexes reconstituted into model membranes
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DOI：
10.1529/biophysj.106.103606
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发表时间：
2007-07-01
影响因子：
3.4
通讯作者：
Oellerich, Silke
中科院分区：
文献类型：
--
作者：
Richter, Martin F.;Baier, Juergen;Oellerich, Silke
利用单分子光谱法研究了紫色细菌Rhodopyramidophilaacidophila（10050株）的捕光2复合物（LH 2）在洗涤剂胶束和脂质膜中的光谱性质。当LH2复合物从其宿主生物膜溶解的非变性洗涤剂，如LDAO，有一个小的2 nm的光谱位移的B850吸收带的合奏光谱。当LH 2复合物被放回磷脂囊泡中时，这是逆转的，即。即，一个更像本地人的环境洗涤剂溶解的LH 2复合物的单分子水平上的光谱特性进行了比较，与那些重组到脂质膜，看看他们的详细的光谱行为。由B850吸收带位置的这些微小变化引起。详细分析了低温单分子。在这两种不同条件下LH 2复合物的荧光激发光谱没有显示出显著差异。特别地，在B850吸收带的圆形k = 61激子状态之间的光谱分裂的分布和k = 61激子状态之间的相互角度的分布在两种情况下是相同的。因此，可以得出结论，LH2络合物来自Rps。嗜酸菌在溶解于洗涤剂胶束中时与它们在膜重构时一样稳定。此外，当将它们溶解在合适的去污剂中并旋涂到表面上用于单分子实验时，它们不会显示出比在磷脂膜中更多的结构紊乱。
The spectroscopic properties of the light-harvesting 2 complexes (LH2) from the purple bacterium Rhodopseudomonas acidophila (strain 10050) in detergent micelles and reconstituted into lipid membranes have been studied by single-molecule spectroscopy. When LH2 complexes are solubilized from their host biological membranes by nondenaturing detergents, such as LDAO, there is a small 2-nm spectral shift of the B850 absorption band in the ensemble spectrum. This is reversed when the LH2 complexes are put back into phospholipid vesicles, i. e., into a more native-like environment. The spectroscopic properties on the single-molecule level of the detergent-solubilized LH2 complexes were compared with those reconstituted into the lipid membranes to see if their detailed spectroscopic behavior was in. uenced by these small changes in the position of the B850 absorption band. A detailed analysis of the low-temperature single-molecule. fluorescence-excitation spectra of the LH2 complexes in these two different conditions showed no significant differences. In particular, the distribution of the spectral splitting between the circular k = 61 exciton states of the B850 absorption band and the distribution of the mutual angle between the k = 61 exciton states are identical in both cases. It can be concluded, therefore, that the LH2 complexes from Rps. acidophila are equally stable when solubilized in detergent micelles as they are when membrane reconstituted. Moreover, when they are solubilized in a suitable detergent and spin coated onto a surface for the single-molecule experiments they do not display any more structural disorder than when in a phospholipid membrane.