Investigation of the functional mechanisms of artificial photosynthetic pigment-protein supra-molecular complexes

人工光合色素蛋白超分子复合物功能机制研究

• 批准号: 14340090
• 负责人: HASHIMOTO Hideki
• 金额: $ 8.58万
• 依托单位: Osaka City University
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (B)
• 财政年份: 2002
• 资助国家: 日本
• 起止时间: 2002 至 2004
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-14340090/
• 关键词: photosynthesis; antenna pigment-protein complex; Reaction center; artificial pigment-protein complex; carotenoid; Ultrafast laser spectroscopy; electroabsorption spectroscopy; X-ray crystallography

Three different kinds of pigment-protein complexes (two antennae called LH2 and LH1, and reaction center (RC)) are deeply involved in the primary process of purple photosynthetic bacteria. In this research project, for the deeper understanding of the functional mechanisms of these pigment-protein complexes, artificial pigment-protein complexes in which the structure of the carotenoid pigments were modified by utilizing organic synthesis were extensively studied. The following remarkable features have been achieved.1.Achievement of the large-scale total synthesis of analogue carotenoids : Larges-scale total syntheses of a series of analogue carotenoids of spheroidene, spirilloxanthin, and lycopene which have different extent of conjugation were achieved.2.X-ray crystallography of the reaction centers in which the analogue carotenoids have been incorporated : The analogue carotenoids of spheroidene were incorporated into the carotenoidless reaction center (RC) from a photosynthetic bacte … More rium Rhodobacter sphaeroides strain R26.1. Thus prepared artificial RCs were crystallized and their crystal structures were determined by X-ray crystallography. These structure analyses revealed the unidirectional insertion of the carotenoid molecule when it is incorporated into the RC. PheM162 is a gate-keeper amino-acid residue, while TrpM75 is a locking amino-acid residue when the carotenoid molecule is re-incorporated into the R26.1 RC.3.Electroabsorption spectroscopy on the native LH2 antenna complex : Electroabsorption spectroscopy using dual-phase lock-in detection was proposed to be one of the most promising methods to detect the electrostatic interaction between the pigments and apoproteins in the pigment-protein complexes. Exact experimental protocols together with the analysis methods were constructed, and they were applied to the native LH2 complex from a photosynthetic bacterium Rb, sphaeroides strain GIC.4.Electroabsorption spectroscopy of the artificial reaction centre in which an analogue carotenoid has been re-incorporated : Electroabsorption spectroscopy was applied to the carotenoidless reaction centre (RC) from Rb. sphaeroides strain R26.1 as well as the same RC in which an analogue carotenoid has been incorporated. We have, for the first time, quantitatively determined the difference of the electrostatic environment induced by the presence or absence of a carotenoid molecule around the bacteriochlorophyll molecules bound to the RC.5.Sub-20 fs time-resolved absorption spectroscopy of carotenoids : Time-resolved absorption spectroscopy with unprecedented temporal resolution of sub-20 fs was applied to f3-carotene and lycopene. The intermediate singlet excited-state (Sx state) in-between the one-photon allowed 1^1B_u^+(S_2) and forbidden 2^1Ag^-(S_1) states was time-resolved for the first time in the real time-domain, and it was evidenced that this intermediate excited state was involved in the relaxation process following the photoexcitation up to the 1^1B_u^+ state. This study was extended to the series of carotene molecules which have different polyene chain-lengths. Except the case of the carotene molecule having 5 conjugated C=C bonds, all the carotene molecules were evidenced in real time-domain to have the S_x state in the relaxation process from S_2 to S_1.6.Reorganization of the LHI antenna complex of Rs. rubrum and its electroabsorption spectroscopy : Carotenoid-free monomeric subunits of B880 pigment-protein complex from Rs. rubrum strain G9+ was reorganized with purified all-trans-spirilloxanthin to form the artificial light-harvesting 1(LH1) complex. Electroabsorption spectroscopy was applied to thus reconstituted LH1 in order to evaluate electrostatic interaction between pigments and apo-proteins in the complex. Less

三种不同类型的色素-蛋白质复合体(两个称为LH2和LH1的触角和反应中心(RC))深入参与了紫色光合细菌的初级过程。在本研究项目中，为了更深入地了解这些色素-蛋白质复合体的作用机理，本研究对利用有机合成方法对类胡萝卜素色素进行结构修饰的人工色素-蛋白质复合体进行了广泛的研究。1.实现了类胡萝卜素的大规模全合成：实现了一系列具有不同偶联程度的类胡萝卜素的大规模全合成。2.类胡萝卜素被掺入的反应中心的X射线晶体学研究：从一株光合杆菌…中将类胡萝卜素掺入无类胡萝卜素反应中心(RC)球形红细菌R26.1菌株较多。对所制备的人造RCS进行了晶化处理，并用X-射线单晶衍射法测定了其晶体结构。这些结构分析表明，当类胡萝卜素分子被掺入RC时，它是单向插入的。PheM162是一个守门人氨基酸残基，而TrpM75是类胡萝卜素分子重新结合到R26.1 RC.3上时的一个锁定氨基酸残基。3.天然LH2天线复合体的电吸收光谱：双相锁定检测的电吸收光谱被认为是检测色素-蛋白质复合体中色素和脱脂蛋白之间静电相互作用的最有前途的方法之一。建立了精确的实验方案和分析方法，并将它们应用于来自光合细菌RB的天然LH2复合体，球形球状杆菌GIC。4.重新加入类胡萝卜素的人工反应中心的电吸收光谱：将电吸收光谱应用于来自RB的无类胡萝卜素反应中心(RC)。球状芽孢杆菌R26.1菌株以及加入类胡萝卜素类似物的同一RC。我们首次定量地确定了类胡萝卜素分子与RC.5结合的细菌叶绿素分子周围存在或不存在的类胡萝卜素分子所引起的静电环境的差异。5.类胡萝卜素的时间分辨吸收光谱：时间分辨吸收光谱具有前所未有的亚20fs的时间分辨率，应用于f3-胡萝卜素和番茄红素。首次在实时域内对处于允许1^1B_u^+(S_2)和禁止2^1AG^-(S_1)态之间的中间单重态激发态(Sx态)进行了时间分辨，并证明该中间激发态参与了光激发到1^1B_u^+态的驰豫过程。这项研究被扩展到具有不同多烯链长的胡萝卜素分子系列。在从S_2到S_1.6的驰豫过程中，除了胡萝卜素分子中有5个共轭C=C键外，所有的胡萝卜素分子都具有S_x态。Rs的LHI天线复合体的重组。红色及其电吸收光谱：来自红色的B880色素-蛋白质复合体的无胡萝卜素单体亚基。红曲霉菌株G9+与纯化的全反式螺黄素重组形成人工捕光1(LH1)复合体。将电吸收光谱应用于这种重组的LH1，以评估色素与络合物中脱脂蛋白之间的静电相互作用。较少

项目成果

Comparative study of different content in chlorophylls, carotenoids, vitamin C, E and Minerals among various vegetable crops

不同蔬菜作物叶绿素、类胡萝卜素、维生素C、E及矿物质含量不同的比较研究

• 发表时间: 2003
• 期刊: 日本食生活学会誌 13
• 作者: H.Inoue;R.Tateishi;Y.Kimura;Y.Ozawa;K.Isobe;K.Nomura;T.Maoka;H.Hashimoto;S.Hirota
• 通讯作者: S.Hirota

Metabolism and the effects on anti-oxidant activity of carotenoids fed on vitamin A deficient rats; the effect of additional sodium cholate

维生素A缺乏大鼠体内类胡萝卜素的代谢及其抗氧化活性的影响

• 发表时间: 2002
• 期刊: Carotenoid Science 5
• 作者: S.Hirota;H.Inoue;A.Tateishi;K.Sekimoto;J.Yokoyama;H.Funayama;F.Hirahata;M.Oyaizu;H.Hashimoto
• 通讯作者: H.Hashimoto

共役ポリエン分子の光反応制御方法

控制共轭多烯分子光反应的方法

• 发表时间: 2003

H.Hashimoto, K.Yanagi, M.Yoshizawa, D.Polli, G.Cerullo, G.Lanzani, S.De Silvestri, A.T.Gardiner, R.J.Cogdell: "The very early events following photoexcitation of carotenoids"Arch. Biochem. Biophys.. (In press). (2004)

H.Hashimoto、K.Yanagi、M.Yoshizawa、D.Polli、G.Cerullo、G.Lanzani、S.De Silvestri、A.T.Gardiner、R.J.Cogdell：“类胡萝卜素光激发后的早期事件”Arch。

R.J.Cogdell, H.Hashimoto, A.T.Gardiner: "Purple bacterial light-harvesting complexes: from dreams to structures"Photosynth.Res.. (In press). (2004)

R.J.Cogdell、H.Hashimoto、A.T.Gardiner：“紫色细菌光捕获复合物：从梦想到结构”Photosynth.Res..（正在出版）。