Self-Assembly of Light-Harvesting Complex for An Artificial Photosynthetic Antenna System and Its Functional Analysis

光反应发生在光合细菌中捕光（LH）-α和-β多肽与反应中心（RC）复合物的紧密耦合的色素系统中;光能被结合到LH多肽的激发耦合天线色素吸收，并且激发能被有效地运输到RC。因此，LH 1复合物与激子耦合的色素的建设将是有用的研究结构和能量传递通过individualpigment.We现在报告的分子组装体的细菌叶绿素（BChla和锌BChla）使用LH多肽分离光合细菌在电极上。LH多肽在电极上形成Zn-BChl a复合物，同时也形成BChl a复合物，其中LH多肽N端或C端的极性氨基酸对复合物的形成起着关键作用。复合物的稳定性取决于脂质双层的结构。电极上络合物形成的证明 ...更多信息 通过监测BChl a或Zn-BChl a的Qy吸收带位移，注意到其中Qy带红移。锌-BChl a复合物比BChl a复合物更稳定。紫外-可见，进一步研究了重组捕光1（LH 1）复合物在氨基端ITO电极（APS-ITO）和LH 1-RC“核心”复合物上的固定化。我们最近的工作将这种方法扩展到使用LH-α和-β多肽与细菌叶绿素的组合作为天然LH和RC复合物。这些复合物被固定在电极上。通过近红外吸收光谱证实了配合物在电极上的组装。这些数据表明，LH -α和-β多肽与BCHa或Zn-BChl a组成的LH 1型复合物在室温下稳定地组装在电极上以及用脂质双层修饰的GC和ITO上。这些吸收光谱是有用的，以证明在880 nm的照明诱导的光电流响应，显示细菌叶绿素和这些电极之间的电子转移。有趣的是，这些电极上的光电流依赖于LH复合物的结构和光的波长，以及脂质双层的结构。作用光谱在配合物的吸收带处有一最大值。少

The light reactions occur in closely coupled pigment systems of the light-harvesting (LH) -α and -β polypeptides and reaction center (RC) complexes in photosynthetic bacteria ; light energy is absorbed by excitonically coupled antenna pigments bound to the LH polypeptides, and the excitation energy is efficiently transported to RC. Thus, the construction of the LH 1 complex with the excitonically coupled pigments will be useful for studying the structure and the energy transfer via individual pigments.We now report molecular assemblies of bacteriochlorophylls (BChl a &Zn-BChl a) using LH polypeptides separately isolated from photosynthetic bacteria on electrodes. The LH polypeptides organized Zn-BChl a complex on electrodes as well as BChl a complex, where polar amino acids at N-or C-terminal of the LH polypeptides performed a crucial role on the complex-formation. The stability of the complexes depended upon the structure of lipid bilayers. The proof of the complex-forming on electrod … More es was noted by monitoring the Qy absorption band-shift of BChl a or Zn-BChl a, where the Qy band was red-shifted. The Zn-BChl a complex in lipid bilayers was more stable than BChl a complex. UV-vis., CD and AFM data of these pigment complexes assembled with the LH polypeptides in lipid bilayers were analogous to those of the LH1-type complex of these photosynthetic bacterias.Further, successful immobilizations of reconstituted light-harvesting 1 (LH1) complexes onto amino terminated ITO electrode (APS-ITO) as well as the LH1-RC 'core' complex were studied. Our recent work extends this approach to using the combination of the LH-α and -β polypeptides and bacteriochlorophylls as the native LH and RC complexes. These complexes were immobilized onto the electrode. The assembly of the complexes on the electrode was confirmed by Near-IR absorption spectroscopy. These data showed that the LH1-type complex consisting of the LH -α and -β polypeptides with BCH a or Zn-BChl a was stably assembled on the electrode at room temperature as well as on a GC and an ITO modified with lipid bilayers. These absorption spectra were usefull to demonstrate the photocurrent response induced by illumination at 880 nm, showing electron transfer between bacteriochlorophylls and these electrodes. Interestingly, the photoelectric current on these electrodes depended on the structures of the LH complexes and the wavelength of the light, and the structure of lipid bilayers. The action spectra revealed a maximum at the wavelength corresponding to the absorption band of the complexes. Less