Binding specificity of a baby hamster kidney lectin for H type I and II chains, polylactosamine glycans, and appropriately glycosylated forms of laminin and fibronectin.
The carbohydrate binding specificity of Mr = 30,000 lectin (CBP30) from baby hamster kidney (BHK) cells has been studied by inhibition of binding of the radiolabeled lectin to asialofetuin-Sepharose using model oligosaccharides and glycopeptides. CBP30 binds type I or II Gal beta(1----3(4))GlcNAc chains but not Gal(beta 1----3)GalNAc. The inhibitory potency of straight chain polylactosamine structures or complex-type branched glycans is increased in proportion to the number of Gal(beta 1----3(4)) units present. Fucosylation or sialylation of terminal galactose residues or further substitution by (alpha 1----3)-linked galactose or N-acetylgalactosamine does not affect binding whereas substitution of the penultimate N-acetylglucosamine residue drastically reduces binding. Thus, blood group A, H type I or H type II structures, shows high affinity whereas Lex, Lea, and Leb structures bind poorly. CBP30 binds to murine Engelbreth-Holm-Swarm (EHS) tumor laminin and human amniotic fluid fibronectin but not human plasma fibronectin. Binding involves polylactosamine glycans as well as tri- and tetraantennary complex-type glycans present in EHS laminin and amniotic fluid fibronectin but absent in plasma fibronectin. Proteolytic fragments of EHS laminin (E1X/Nd, P1, E8, and E3) bind CBP30, but only fragment E8 supports attachment and spreading of BHK cells. BHK cell adhesion to EHS laminin or fragment E8 was not disturbed by CBP30-specific antibodies, but at relatively high concentrations (45 micrograms/ml) CBP30 inhibited spreading and partially attachment of cells on laminin.
Sato
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National Institute for Medical Research, Mill Hill, London, United Kingdom.
Hughes
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D000117:Acetylglucosamine / Q000378:metabolism; D000818:Animals; D015153:Blotting, Western; D002240:Carbohydrate Sequence; D002352:Carrier Proteins / Q000037:antagonists & inhibitors / Q000378:metabolism; D002448:Cell Adhesion; D002460:Cell Line; D006224:Cricetinae; D004591:Electrophoresis, Polyacrylamide Gel; D004797:Enzyme-Linked Immunosorbent Assay; D005353:Fibronectins / Q000378:metabolism*; D006031:Glycosylation; D006801:Humans; D007668:Kidney / Q000166:cytology / Q000378:metabolism*; D007797:Laminin / Q000378:metabolism*; D037102:Lectins / Q000378:metabolism*; D007983:Lewis Blood Group Antigens / Q000378:metabolism; D008969:Molecular Sequence Data; D011134:Polysaccharides / Q000378:metabolism*; D011956:Receptors, Cell Surface / Q000378:metabolism; D013379:Substrate Specificity
D002352:Carrier Proteins; D005353:Fibronectins; D007797:Laminin; D037102:Lectins; D007983:Lewis Blood Group Antigens; D011134:Polysaccharides; D011956:Receptors, Cell Surface; C055213:saccharide-binding proteins; D000117:Acetylglucosamine