The D-galactose-binding lectin of the octocoral Sinularia lochmodes: characterization and possible relationship to the symbiotic dinoflagellates.
A D-galactose binding lectin (SLL-2) was isolated from Sinularia lochmodes, an octocoral, by a combination of affinity chromatography on acid-treated agarose and FPLC on Superdex 200. SLL-2 agglutinated rabbit and horse erythrocytes while SLL-1, a minor component, reacted only with rabbit erythrocytes. SLL-2 is a glycoprotein with a molecular mass of 122 kDa and is composed of eight identical subunits (15 kDa). The sequence of the amino terminal region of SLL-2 did not show any apparent homology to the sequences of other animal and plant lectins. D-Galactose, N-acetyl-D-galactosamine, lactose, and melibiose were moderate inhibitors to the agglutination of rabbit erythrocytes. In contrast, horse erythrocytes were much more susceptible to agglutination by SLL-2, which was inhibited by sugars and glycoproteins such as D-galactose, N-acetyl-D-galactosamine, lactose, melibiose, and porcine stomach mucin. SLL-2 showed considerable tolerance to heating and kept its activity after heating at 80 degrees C for 60 min. In immuno-histochemical studies using an anti-SLL-2 antiserum and protein A gold conjugate, SLL-2 was found to be present in high amounts in the nematocysts. SLL-2 was also detected on the surface of symbiotic dinoflagellate, Symbiodinium sp. cells irrespective whether they were surrounded with or without host cells. These observations suggest the presence of lectin-mediated interaction between symbiotic dinoflagellates and S. lochmodes.
Jimbo
M
M
Department of Marine Biochemistry, Faculty of Fisheries Sciences, Kitasato University, Iwate, Japan.
Yanohara
T
T
Koike
K
K
Koike
K
K
Sakai
R
R
Muramoto
K
K
Kamiya
H
H
D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D002846:Chromatography, Affinity; D003063:Cnidaria / Q000737:chemistry* / Q000648:ultrastructure; D004141:Dinoflagellida / Q000378:metabolism* / Q000648:ultrastructure; D004589:Electrophoresis, Disc; D004591:Electrophoresis, Polyacrylamide Gel; D005690:Galactose / Q000378:metabolism* / Q000494:pharmacology; D020459:Genes, rRNA / Q000235:genetics; D006386:Hemagglutination Tests; D037102:Lectins / Q000737:chemistry / Q000302:isolation & purification / Q000378:metabolism*; D008854:Microscopy, Electron; D008969:Molecular Sequence Data; D009004:Monosaccharide Transport Proteins / Q000737:chemistry / Q000302:isolation & purification / Q000378:metabolism*; D011817:Rabbits; D016415:Sequence Alignment; D013559:Symbiosis
D037102:Lectins; D009004:Monosaccharide Transport Proteins; C415124:SLL-2 protein, Sinularia lochmodes; D005690:Galactose