The specificity of the binding site of AchatininH, a sialic acid-binding lectin from Achatina fulica.
A sialic acid-binding lectin, AchatininH (ATNH), having unique specificity towards 9-O-acetylneuraminic acid, has been purified and characterized. The specificity of this lectin for O-acetylsialic acids was studied in detail, using various sialic acid derivatives and sialoglycoproteins. The potent inhibition of hemagglutination by bovine submaxillary mucin (BSM), which contains 9(7,8)-O-acetylsialic acid and by free 9-O-acetylneuraminic acid confirms the preferential affinity towards this sugar. Further support for the role of O-acetylsialic acid was obtained by sialidase treatment of BSM. O-Deacetylation of the sialic acid residue abolished its inhibitory potency. Moreover, when the trihydroxypropyl side chain of the sialic acid molecule was modified by periodate-borohydride treatment, the truncated C7-sialic acid was unable to bind ATNH. This result suggests that the glycerol side chain of Neu5Ac, especially the C-8 and/or C-9 portion is an important determinant for ATNH. The hemagglutination-inhibition results using several mono-, di-, and tri-saccharides containing terminal sialic acid and various sialoglycoproteins reveals that ATNH preferentially binds the alpha-(2-->6)-linked sialic acid. Furthermore, beta-D-GlcNAc-(1-->3)-[alpha-NeuGc-(2-->6)]-GalNAc-ol was found to be the best ligand for ATNH.
Sen
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Indian Institute of Chemical Biology, Calcutta.
Mandal
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C
D000818:Animals; D001665:Binding Sites; D001667:Binding, Competitive; D001894:Borohydrides / Q000494:pharmacology; D002240:Carbohydrate Sequence; D006384:Hemagglutination / Q000187:drug effects; D006385:Hemagglutination Inhibition Tests; D037102:Lectins / Q000737:chemistry* / Q000302:isolation & purification / Q000378:metabolism; D008969:Molecular Sequence Data; D009077:Mucins / Q000378:metabolism / Q000494:pharmacology; D009439:Neuraminidase / Q000378:metabolism / Q000494:pharmacology; D009844:Oligosaccharides / Q000494:pharmacology; D010504:Periodic Acid / Q000494:pharmacology; D012794:Sialic Acids / Q000378:metabolism* / Q000494:pharmacology; D012795:Sialoglycoproteins / Q000378:metabolism / Q000494:pharmacology; D012908:Snails
D001894:Borohydrides; D037102:Lectins; D009077:Mucins; D009844:Oligosaccharides; D012794:Sialic Acids; D012795:Sialoglycoproteins; C033259:acetylsialomucin; C050704:achatinin(H); C016735:sialooligosaccharides; D010504:Periodic Acid; C025676:9-O-acetyl-N-acetylneuraminic acid; D009439:Neuraminidase