Molecular modeling and mutagenesis studies of the N-terminal domains of galectin-3: evidence for participation with the C-terminal carbohydrate recognition domain in oligosaccharide binding.
A model structure (Henrick,K., Bawumia,S., Barboni,E.A.M., Mehul,B. and Hughes, R.C. (1998) Glycobiology:, 8, 45-57) of the carbohydrate recognition domain (CRD, amino acid residues 114-245) of hamster galectin-3 has been extended to include N-terminal domain amino acid residues 91-113 containing one of the nine proline-rich motifs present in full-length hamster galectin-3. The modeling predicts two configurations of the N-terminal tail: in one the tail turns toward the first (SI) and last (S12) beta-strands of the CRD and lies at the apolar dimer interface observed for galectins -1 and -2. In the second folding arrangement the N-terminal tail lies across the carbohydrate-binding pocket of the CRD where it could participate in sugar-binding: in particular tyrosine 102 and adjacent residues may interact with the partly solvent exposed nonreducing N-acetylgalactosamine and fucose substituents of the A-blood group structure GalNAcalpha1,3 [Fucalpha1,2]Galbeta1,4GlcNAc-R. Binding studies using surface plasmon resonance of a recombinant fragment Delta1-93 protein containing residues 94-245 of hamster galectin-3 and a collagenase-derived fragment Delta1-103 containing residues 104-245, as well as alanine mutagenesis of residues 101-105 in Delta1-93 protein, support the prediction that Tyr102 and adjacent residues make significant contributions to oligosaccharide binding.
Barboni
E A
EA
National Institute for Medical Research, Mill Hill, London NW7 1AA, UK.
Bawumia
S
S
Henrick
K
K
Hughes
R C
RC
D000595:Amino Acid Sequence; D000818:Animals; D000943:Antigens, Differentiation / Q000737:chemistry* / Q000235:genetics* / Q000378:metabolism; D001483:Base Sequence; D001665:Binding Sites / Q000235:genetics; D006224:Cricetinae; D017931:DNA Primers / Q000235:genetics; D037502:Galectin 3; D006241:Haptens / Q000494:pharmacology; D066298:In Vitro Techniques; D007700:Kinetics; D007797:Laminin / Q000378:metabolism; D037102:Lectins / Q000378:metabolism; D008958:Models, Molecular; D008969:Molecular Sequence Data; D016297:Mutagenesis, Site-Directed; D009844:Oligosaccharides / Q000378:metabolism; D011487:Protein Conformation; D017434:Protein Structure, Tertiary; D020349:Surface Plasmon Resonance
D000943:Antigens, Differentiation; D017931:DNA Primers; D037502:Galectin 3; D006241:Haptens; D007797:Laminin; D037102:Lectins; D009844:Oligosaccharides