title: Systematic comparison of oligosaccharide specificity of Ricinus communis agglutinin I and Erythrina lectins: a search by frontal affinity chromatography.
abstract: Ricinus communis agglutinin I (RCA120) is considered a versatile tool for the detection of galactose-containing oligosaccharides. However, possible contamination by the highly toxic isolectin 'ricin' has become a critical issue for RCA120's continued use. From a practical viewpoint, it is necessary to find an effective substitute for RCA120. For this purpose, we examined by means of frontal affinity chromatography over 100 lectins which have similar sugar-binding specificities to that of RCA120. It was found that Erythrina cristagalli lectin (ECL) showed the closest similarity to RCA120. Both lectins prefer Gal beta1-4GlcNAc (type II) to Gal beta1-3GlcNAc (type I) structures, with increased affinity for highly branched N-acetyllactosamine-containing N-glycans. Their binding strength significantly decreased following modification of the 3-OH, 4-OH and 6-OH of the galactose moiety of the disaccharide, as well as the 3-OH of its N-acetylglucosamine residue. Several differences were also observed in the affinity of the two lectins for various other ligands, as well as effects of bisecting GlcNAc and terminal sialylation. Although six other Erythrina-derived lectins have been reported with different amino acid sequences, all showed quite similar profiles to that of ECL, and thus, to RCA120. Erythrina lectins can therefore serve as effective substitutes for RCA120, taking the above differences into consideration.
authors.affiliation: Lectin Application and Analysis Team, Research Center for Medical Glycoscience, National Institute of Advanced Industrial Science and Technology, Tsukuba Central 2, 1-1-1, Umezono, Tsukuba, Ibaraki 305-8568.
authors.forename: Yoko
authors.initials: Y
authors.lastname: Itakura
authors.forename: Sachiko
authors.initials: S
authors.lastname: Nakamura-Tsuruta
authors.forename: Junko
authors.initials: J
authors.lastname: Kominami
authors.forename: Nathan
authors.initials: N
authors.lastname: Sharon
authors.forename: Ken-Ichi
authors.initials: K
authors.lastname: Kasai
authors.forename: Jun
authors.initials: J
authors.lastname: Hirabayashi
mesh_terms: D002236:Carbohydrate Conformation; D002240:Carbohydrate Sequence; D002846:Chromatography, Affinity / Q000379:methods; D004895:Erythrina / Q000737:chemistry / Q000378:metabolism; D008969:Molecular Sequence Data; D009844:Oligosaccharides / Q000737:chemistry* / Q000378:metabolism; D037121:Plant Lectins / Q000737:chemistry* / Q000378:metabolism; D011485:Protein Binding; D012278:Ricinus / Q000737:chemistry / Q000378:metabolism
chemical_list: D009844:Oligosaccharides; D037121:Plant Lectins; C017707:Ricinus communis agglutinin-1; C045629:erythrina lectin