Klenina I B, Makhneva Z K, Moskalenko A A, Kuz'min A N, Proskuriakov I I
Biofizika. 2013 Jan-Feb;58(1):54-63.
Time-resolved electron paramagnetic resonance was used to study the properties of carotenoid triplet states populated in LH2 light-harvesting complexes of phototrophic bacteria Allochromatium minutissimum, Rhodopseudomonas palustris, and in carotenoid films free of bacteriochlorophyll. The study was performed on purified LH2 preparations not contaminated by reaction centers, and under selective pigment excitation. The obtained results enable a conclusion that the carotenoid triplet states, both in LH2 complexes and films, are populated in the process of homofission of singlet excitation into two triplets, which involves only carotenoid molecules. It is observed that the fission process in magnetic field leads to predominant population of the T0 spin sublevel of the triplet. One molecular spin sublevel of the triplet is demonstrated to possess an increased probability of intersystem crossing to the ground state, independent of the carotenoid configuration. Pigment composition of the LH2 protein heterodimers is discussed, and a conclusion of the possible
利用时间分辨电子顺磁共振研究了光合细菌极小嗜色菌、沼泽红假单胞菌的LH2光捕获复合物以及不含细菌叶绿素的类胡萝卜素薄膜中类胡萝卜素三重态的性质。该研究是在未被反应中心污染的纯化LH2制剂上，以及在选择性色素激发下进行的。所得结果表明，LH2复合物和薄膜中的类胡萝卜素三重态是在单重激发同裂为两个三重态的过程中产生的，该过程仅涉及类胡萝卜素分子。观察到磁场中的裂变过程导致三重态的T0自旋子能级占主导。已证明三重态的一个分子自旋子能级具有增加的系间窜越到基态的概率，与类胡萝卜素构型无关。讨论了LH2蛋白异二聚体的色素组成，并得出了可能的结论。
