Ligand binding characteristics of the major mistletoe lectin.
Carbohydrate binding specificity of the galactose-specific, major lectin of mistletoe extract (ML-1) was studied by an inhibition assay using monosaccharides, monosaccharide derivatives, disaccharides, and compounds containing multiple galactosyl terminals. The results indicate that 1) both alpha- and beta-galactosyl residues are recognized equally well; 2) each of the hydroxyl groups of galactose contributes to varying degrees to the binding process, the 4-OH being the most important and the 6-OH the least important hydroxyl group; 3) disaccharide sequences of Gal beta 2Gal and Gal beta 3Gal have much higher affinity than galactose, whereas affinity of all other Gal-disaccharides is only slightly better than galactose; 4) macromolecular ligands having 10 or more terminal galactosyl residues have 500-fold higher affinity than Gal; and 5) a group on ML-1 with pK alpha of 4.8 appears to be involved in the binding of ligand.
Lee
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RT
Department of Biology, Johns Hopkins University, Baltimore, Maryland 21218.
Gabius
H J
HJ
Lee
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YC
D001665:Binding Sites; D002236:Carbohydrate Conformation; D002240:Carbohydrate Sequence; D004187:Disaccharides / Q000737:chemistry* / Q000378:metabolism; D005697:Galactosides / Q000378:metabolism; D037161:Galectins; D006020:Glycopeptides / Q000737:chemistry* / Q000378:metabolism; D006027:Glycosides / Q000737:chemistry* / Q000378:metabolism; D006388:Hemagglutinins / Q000378:metabolism; D006801:Humans; D007700:Kinetics; D008024:Ligands; D014784:Mistletoe; D008958:Models, Molecular; D008969:Molecular Sequence Data; D009844:Oligosaccharides / Q000138:chemical synthesis / Q000737:chemistry* / Q000378:metabolism; D028321:Plant Preparations; D010940:Plant Proteins; D010946:Plants, Medicinal; D054790:Ribosome Inactivating Proteins, Type 2; D014118:Toxins, Biological / Q000737:chemistry* / Q000378:metabolism
D004187:Disaccharides; D005697:Galactosides; D037161:Galectins; D006020:Glycopeptides; D006027:Glycosides; D006388:Hemagglutinins; D008024:Ligands; D009844:Oligosaccharides; D028321:Plant Preparations; D010940:Plant Proteins; D054790:Ribosome Inactivating Proteins, Type 2; D014118:Toxins, Biological; C009674:ribosome inactivating protein, Viscum