Isolation, properties and a possible function of a water-soluble chlorophyll a/b-protein from brussels sprouts.
Isolation, properties and a possible function of a water-soluble chlorophyll a/b-protein from brussels sprouts.
复制标题
抱子甘蓝中水溶性叶绿素 a/b 蛋白的分离、特性和可能的功能。
作者：
Y. Kamimura;T. Mori;T. Yamasaki;S. Katoh
从布鲁塞尔芽甘蓝（Brassica oleracea L.）变种gemmifera DC）。该蛋白质的分子量为78 kDa，等电点为4.7，由三个或四个22 kDa的亚基组成，具有极高的热稳定性。虽然CP 673每种蛋白质含有一种Chl a，但Chl a的蓝色和红色吸收带由三种或四种具有不同吸收最大值的Chl a形式组成，表明Chl a有几种不同的结合模式或结合位点。Chl a/B比值大于10也表明Chl B仅存在于CP 673的一小部分中。CP 673在Chl的组成和结合方面的异质性表明Chl不是Chl蛋白的内在组分。同源性搜索表明，CP 673的N-末端氨基酸序列是高度同源的，积累在两个油菜科植物，油菜籽和萝卜的水分胁迫叶片中的22 kDa的蛋白质，但不与光合作用的捕光叶绿素a/b-蛋白质。并对该蛋白的可能功能进行了讨论。
A water-soluble Chl a/b-protein (CP673) was isolated and purified from Brussels sprouts (Brassica oleracea L. var. gemmifera DC). The protein had a molecular mass of 78 kDa and an isoelectric point of 4.7, consisted of three or four subunits of 22 kDa and was extremely heat-stable. Although CP673 contained about one Chl a per protein, the blue and red absorption bands of Chl a that consisted of three or four Chl a forms with different absorption maxima suggested that there are several different modes or sites of binding for Chl a. Chl a/b ratio of larger than 10 also indicated that Chl b is present only in a small fraction of CP673. The heterogeneity of CP673 in terms of composition and binding of Chl suggests that Chl is not an intrinsic component of the Chl-protein. Homology search showed that the N-terminal amino acid sequence of CP673 is highly homologous with that of a 22 kDa protein that accumulates in water-stressed leaves of two Brassicaceae plants, rapeseed and radish, but not with those of the light-harvesting Chl a/b-proteins of photosynthesis. A possible function of the water-soluble Chl-protein was discussed.