Inactivation and deficiency of core proteins of photosystems I and II caused by genetical phylloquinone and plastoquinone deficiency but retained lamellar structure in a T-DNA mutant of Arabidopsis
Inactivation and deficiency of core proteins of photosystems I and II caused by genetical phylloquinone and plastoquinone deficiency but retained lamellar structure in a T-DNA mutant of Arabidopsis
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DOI：
10.1111/j.1365-313x.2004.02326.x
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发表时间：
2005-02-01
期刊：
影响因子：
7.2
通讯作者：
Takamiya, K
中科院分区：
文献类型：
--
作者：
Shimada, H;Ohno, R;Takamiya, K
叶绿醌是一种取代的 1,4-萘醌，具有 18 个碳饱和的植基尾部，在光系统 I (PSI) 的 A(1) 位点充当结合单电子载体辅助因子。费尔德曼口号突变体，不。 2755（以下记为abc4），幼叶淡绿色，老叶白色。突变核基因编码1,4-二羟基-2-萘酸植基转移酶，这是一种叶绿醌生物合成酶，高效液相色谱分析显示，abc4突变体不含叶绿醌，仅含有约3%的质体醌。 abc4突变体中PSI的P700没有观察到光氧化，还原与氧化差异光谱表明abc4突变体没有P700。 abc4突变体中光系统II（PSII）的最大量子产率大大降低，并且abc4突变体中没有发生从PSII到PSI的电子转移。对于abc4突变体植物的淡绿色叶片，叶绿体的超微结构与野生型植物几乎相同。然而，突变体白化叶片的叶绿体较小，基粒类囊体较多，基质类囊体较少。与野生型相比，abc4突变体中PSI和PSII核心亚基的数量显着减少。这些结果表明，PSI中叶绿醌的缺乏会导致PSI的消失和由于质体醌显着减少而引起的PSII的部分缺陷，但不影响幼叶叶绿体的超微结构。
Phylloquinone, a substituted 1,4-naphthoquinone with an 18-carbon-saturated phytyl tail, functions as a bound one-electron carrier cofactor at the A(1) site of photosystem I (PSI). A Feldmann tag line mutant, no. 2755 (designated as abc4 hereafter), showed pale-green young leaves and white old leaves. The mutated nuclear gene encoded 1,4-dihydroxy-2-naphtoic acid phytyltransferase, an enzyme of phylloquinone biosynthesis, and high-performance liquid chromatography analysis revealed that the abc4 mutant contained no phylloquinone, and only about 3% plastoquinone. Photooxidation of P700 of PSI in the abc4 mutant was not observed, and reduced-versus-oxidized difference spectroscopy indicated that the abc4 mutant had no P700. The maximum quantum yield of photosystem II (PSII) in the abc4 mutant was much decreased, and the electron transfer from PSII to PSI in the abc4 mutant did not occur. For the pale-green leaves of the abc4 mutant plant, the ultrastructure of the chloroplasts was almost the same as that of the wild-type plant. However, the chloroplasts in the albino leaves of the mutant were smaller and had a lot of grana thylakoids and few stroma thylakoids. The amounts of PSI and PSII core subunits in the abc4 mutant were significantly decreased compared with those in the wild type. These results suggested that a deficiency of phylloquinone in PSI caused the abolishment of PSI and a partial defect of PSII due to a significant decrease of plastoquinone, but did not influence the ultrastructure of the chloroplasts in young leaves.