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Structural role of lipids in molecular architecture of photosystem I in thylakoid membranes.

脂质在类囊体膜光系统 I 分子结构中的结构作用。

基本信息

批准号：
60540433
负责人：
HOSHINA Satoshi
金额：
$ 1.09万
依托单位：
Kanazawa University
依托单位国家：
日本
项目类别：
Grant-in-Aid for General Scientific Research (C)
财政年份：
1985
资助国家：
日本
起止时间：
1985 至 1986
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-60540433/
关键词：
Chlorophyll-protein complex Energy transfer Light-harvesting complex p700 Photosystem I Reconstitution Spinacia oleracea P700

项目摘要

Chlorophyll-protein complexes were isolated from spinach thylakoids. These complexes were designated CPI' (reaction-center enriched photosystem I), and LHCI (light-harvesting Chl a/b-protein complex associated with photosystem I). When CPI' was reconstituted with LHCI into liposomes of soybean phosphatidylcholine (PC), the first-order rate constant for P700-photooxidation (kP700) in proteoliposomes under light-limiting conditions was approximately double that of a mixture of two complexes not reconstituted into liposomes. The fluorescence emission spectrum (77 K) of the proteoliposomes of the two complexes reconstituted into soybean PC displayed a longer wavelength band at 730-733 nm which was not dispalyed in the spectrum of a mixture of CPI' and LHCI without liposomes. The circular dichroism spectrum of the two complexes indicated that the intensities of both a positive peak at 665 nm and a negative peak at 686 nm increased when the two complexes were reconstituted into soybean PC. I … More n order to investigate whether reconstitution with thylakoid lipids would affect kP700, CPI' was reconstituted with LHCI into liposomes of lipids isolated from spinach thylakoids. Reconstitution with acidic lipids (consisted of sulfoquinovosyldiacylglycerol and phosphatidylglycerol) resulted in no effect on kP700. On the other hand, kP700 of a mixture of CPI' and LHCI increased significantly when the two complexes were reconstituted into neutral lipids. In fact reconstitution with monogalactosyldiacylglycerol (containing 20%(W/W) soybean PC for making liposomes) gave a 75% stimulation above kP700 in a mixture of the two complexes without liposomes, and digalactosyldiacylglycerol (containing 20% soybean PC) gave about 30% stimulation. These results results suggest that some alteration of chlorophyll organization occurs in proteoliposomes reconstituted with both CPI' and LHCI, facilitating energy transfer from LHCI to the reaction center of photosystem I, and monogalactosyldiacylglyceride plays an important role in the incorporation of chlorophyll-protein complexes associated with photosystem I into the bilayer of the thylakoid membranes. Less

从菠菜类囊体中分离出叶绿素-蛋白质复合物。这些复合物被命名为CPI'（反应中心富集的光系统I）和LHCI（与光系统I相关的捕光叶绿素a/b-蛋白复合物）。当CPI'与LHCI重组到大豆磷脂酰胆碱（PC）脂质体中时，在光限制条件下，蛋白脂质体中P700-光氧化的一级速率常数（kP 700）约为未重组到脂质体中的两种复合物的混合物的一级速率常数的两倍。两种复合物的脂蛋白体的荧光发射光谱（77 K）在730-733 nm处显示出较长的波长带，这是CPI ′和LHCI混合物的荧光发射光谱所没有的。圆二色性光谱表明，两种复合物在大豆PC中的665 nm处的正峰和686 nm处的负峰强度均有所增加。我 ...更多信息为了研究用类囊体脂质重构是否会影响kP 700，用LHCI将CPI ′重构到从菠菜类囊体分离的脂质的脂质体中。用酸性脂质（由磺基喹诺糖基二酰甘油和磷脂酰甘油组成）重建对kP 700无影响。另一方面，当两种复合物被重构为中性脂质时，CPI ′和LHCI的混合物的kP_（700）显著增加。事实上，在没有脂质体的两种复合物的混合物中，用单半乳糖基二酰基甘油（含有20%（W/W）大豆PC用于制备脂质体）重构得到高于kP 700的75%刺激，并且二半乳糖基二酰基甘油（含有20%大豆PC）得到约30%刺激。这些结果表明，在CPI ′和LHCI重组的蛋白脂质体中，叶绿素结构发生了一些变化，促进了能量从LHCI向光系统I反应中心的转移，并且单半乳糖基二酰甘油酯在与光系统I相关的叶绿素-蛋白复合物掺入类囊体膜双层中起着重要作用。少