Isolation, properties and a possible function of a water-soluble chlorophyll a/b-protein from brussels sprouts [Brassica oleracea gemmifera]
1997
Kamimura, Y. (Toho Univ., Funabashi, Chiba (Japan). Faculty of Science) | Mori, T. | Yamasaki, T. | Katoh, S.
A water-soluble Chl a/b-protein (CP673) was isolated and purified from Burssels 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 these 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
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