Isolation, properties and a possible function of a water-soluble chlorophyll a/b-protein from brussels sprouts.
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.
Kamimura
Y
Y
Department of Biology, Faculty of Science, Toho University, Funabashi, Japan.
Mori
T
T
Yamasaki
T
T
Katoh
S
S
D000595:Amino Acid Sequence; D002734:Chlorophyll / Q000235:genetics / Q000302:isolation & purification* / Q000378:metabolism; D000077194:Chlorophyll A; D045342:Light-Harvesting Protein Complexes; D008969:Molecular Sequence Data; D045322:Photosynthetic Reaction Center Complex Proteins / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism; D010940:Plant Proteins / Q000235:genetics / Q000302:isolation & purification* / Q000378:metabolism; D011480:Protease Inhibitors / Q000302:isolation & purification / Q000378:metabolism; D017386:Sequence Homology, Amino Acid; D014675:Vegetables / Q000235:genetics / Q000378:metabolism*
D045342:Light-Harvesting Protein Complexes; D045322:Photosynthetic Reaction Center Complex Proteins; D010940:Plant Proteins; D011480:Protease Inhibitors; D002734:Chlorophyll; C037184:chlorophyll b; D000077194:Chlorophyll A