Elucidation of the Molecular Properties of Chlorophyll a' and Its Function in Photosynthetic Reaction Centers

叶绿素a的分子性质及其在光合反应中心的功能的阐明

• 批准号: 08455391
• 负责人: WATANABE Tadashi
• 金额: $ 4.8万
• 依托单位: The University of Tokyo
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (B)
• 财政年份: 1996
• 资助国家: 日本
• 起止时间: 1996 至 1997
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-08455391/
• 关键词: chlorophyll a'; photosynthesis; reaction center; photosystem I; P700; HPLC; dimer; クロロフィルa′; クロロフィル; 分子間会合; 二量化; 分光特性

1. Chlorophyll a', in sharp contrast to the ordinary chlorophyll a, forms aggregates with its dimer as the building block, in aqueous alkohols and surfactant aqueous solutions. In view of the long-standing hypothesis that the PSI reaction center, P700, consists of a dimeric chlorophyll, this finding supports an idea that chlorophyll a' constitutes P700 itself.2. By use of barley and cucumber as samples, an HPLC condition has been established that can separate and identify a number of biosynthetic intermediates of chlorophyllous pigments, even for the very early phase of greening of etiolated leaves where only a miniscule amount of chlorophylls are being biosynthesized.3. The greening process of etiolated barley and cucumber has been closely examined with the above-established chromatographic technique. As a result, the relative amount of chlorophyll a' has been found to increase abruptly, in ca. 1 h after the start of greening, to a level more than twice that in mature leaves : this indicates that chlorophyll a' is indeed biosynthesized as an ingredient of the photosynthetic core pigment-protein complexes. Simultaneous examination of the amount of P700 in the course of greening yielded a stoichiometry of chlorophyll a'/P700=2 except for a very early phase, supporting the idea that this minor pigment is functioning in close association with P700.

1.与普通叶绿素a形成鲜明对比的是，叶绿素a '在醇水溶液和表面活性剂水溶液中以其二聚体作为结构单元形成聚集体。鉴于PSI反应中心P700由二聚体叶绿素组成的长期假设，这一发现支持了叶绿素a'本身构成P700的想法。以大麦和黄瓜为样品，建立了高效液相色谱条件，该条件可以分离和鉴定大量叶绿素的生物合成中间体，即使是在黄化叶片变绿的非常早期阶段，其中只有极少量的叶绿素被生物合成.用上述建立的色谱技术对黄化大麦和黄瓜的绿化过程进行了仔细的研究。结果发现，叶绿素a'的相对量在约100 ℃时突然增加。开始变绿后1小时，达到成熟叶的两倍以上的水平：这表明叶绿素a'确实是作为光合核心色素-蛋白质复合物的成分生物合成的。同时检查的P700的量在绿化的过程中产生的化学计量叶绿素a '/P700=2，除了非常早期的阶段，支持的想法，这种次要的色素是功能密切相关的P700。

项目成果

T.Oba, T.Watanabe, M.Mimuro, M.Kobayashi, S.Yoshida: "Aggregation of Chlorophyll a' in Aqueous Methanol" Photochem.Photobiol.Vol.63, No.5. 639-648 (1996)

T.Oba、T.Watanabe、M.Mimuro、M.Kobayashi、S.Yoshida：“甲醇水溶液中叶绿素 a 的聚集” Photochem.Photobiol.Vol.63，No.5。

渡辺正(訳): "地球環境化学入門" シュプリンガー・フェアラーク東京, 270 (1997)

Tadashi Watanabe（译者）：《全球环境化学导论》Springer Verlag Tokyo，270（1997）

渡辺 正(訳): "地球環境科学入門" シュプリンガー・フェアラーク東京, 270 (1997)

Tadashi Watanabe（译者）：《地球环境科学导论》Springer Verlag Tokyo，270（1997）

M.Kobayashi, M.Akiyama, T.Watanabe, H,Kise: "Classification of Photosynthetic Reaction Centers Based on the Chlorophyll Species" Biophysics (Seibutsu-Butsuri). Vol.37, No.5 (in Japanese). 196-200 (1997)

M.Kobayashi、M.Akiyama、T.Watanabe、H、Kise：“基于叶绿素种类的光合反应中心分类”生物物理学（Seibutsu-Butsuri）。

A.Nakamura, T.Watanabe: "HPLC Determination of Photosynthetic Pigments during Greening of Etiolated Barley Leaves. Evidence for the Biosynthesis of Chlorophyll a'" FEBS Lett.(in press). (1998)

A.Nakamura、T.Watanabe：“黄化大麦叶变绿过程中光合色素的 HPLC 测定。叶绿素生物合成的证据 a”FEBS Lett。（正在出版）。