Reconstitution of photosynthetic reaction centers and core antenna-reaction center complexes in liposomes and their thermal stability
Reconstitution of photosynthetic reaction centers and core antenna-reaction center complexes in liposomes and their thermal stability
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DOI：
10.1271/bbb.69.1130
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发表时间：
2005-06-01
影响因子：
1.6
通讯作者：
Nozawa, T
中科院分区：
文献类型：
--
作者：
Kobayashi, M;Fujioka, Y;Nozawa, T
从嗜热嗜热菌ThermochromiumT. tepidum和嗜温菌Allochromatium（A.）将vinosum重构为脂质体。在约4 ℃和40 ℃下，从吸收光谱分别发现重构脂质体中的RC和LH 1-RC是完整的。对T.脂质体中的Tepidum取决于它们是否被脂质直接包围或被核心捕光复合物包围。的.结果表明，T. tepidum通过与LH 1的相互作用获得其热稳定性。这些结果与LH 1在T. tepidum在重构的LH 1-RC脂质体和ICM中是相似的。这与嗜温细菌A. vinosum。RC的热稳定性也受到其亚基组成的影响：RC含有细胞色素亚基是更热稳定性比细胞色素分离RC。这表明细胞色素亚基可能在保护特殊的色素对不变性中起作用。热变性反应对时间呈二级反应。色素与蛋白质和/或脂质的相互作用可能是二级反应曲线的原因。
Photosynthetic reaction centers (RCs) and their core light-harvesting complexes (LM-RCs), purified from a thermophile, Thermochromatium (T.) tepidum, and a mesophile, Allochromatium (A.) vinosum, were reconstituted into liposomes. The RC and the LH1-RC in the reconstituted liposomes were found intact from the absorption spectra at about 4 and 40 degrees C respectively. The thermal stability of the RCs of T. tepidum in the liposome was dependent on whether they were surrounded directly by lipids or-by the core light-harvesting complexes. The. results show that the RC of T. tepidum gains its thermostability through interactions with the LH1. These results are consistent with the result that the thermal stability of the LH1 in T. tepidum is similar in both the reconstituted LH1-RC liposome and ICM. This is clearly different from the mesophilic bacterium, A. vinosum. The thermal stability of RC was also affected by its subunit constitution: the RC containing a cytochrome subunit was more thermostable than the cytochrome-detached RC. This suggests that the cytochrome subunit might play a role in protecting the special pair pigments from denaturation. The thermal denaturation showed a second-order reaction dependence on time. The interaction of the pigments with proteins and/or lipids might be the cause of the second-order reaction profile.