1AFB
STRUCTURAL BASIS OF GALACTOSE RECOGNITION IN C-TYPE ANIMAL LECTINS
Summary for 1AFB
| Entry DOI | 10.2210/pdb1afb/pdb |
| Descriptor | MANNOSE-BINDING PROTEIN-A, 2-acetamido-2-deoxy-beta-D-galactopyranose, CALCIUM ION, ... (5 entities in total) |
| Functional Keywords | c-type lectin, calcium-binding protein, lectin |
| Biological source | Rattus norvegicus (Norway rat) |
| Total number of polymer chains | 3 |
| Total formula weight | 52171.12 |
| Authors | Kolatkar, A.R.,Weis, W.I. (deposition date: 1995-11-03, release date: 1996-04-03, Last modification date: 2024-11-20) |
| Primary citation | Kolatkar, A.R.,Weis, W.I. Structural basis of galactose recognition by C-type animal lectins. J.Biol.Chem., 271:6679-6685, 1996 Cited by PubMed Abstract: The asialoglycoprotein receptors and many other C-type (Ca2+-dependent) animal lectins specifically recognize galactose- or N-acetylgalactosamine-terminated oligosaccharides. Analogous binding specificity can be engineered into the homologous rat mannose-binding protein A by changing three amino acids and inserting a glycine-rich loop (Iobst, S. T., and Drickamer, K. (1994) J. Biol. Chem. 269, 15512-15519). Crystal structures of this mutant complexed with beta-methyl galactoside and N-acetylgalactosamine (GalNAc) reveal that as with wild-type mannose-binding proteins, the 3- and 4-OH groups of the sugar directly coordinate Ca2+ and form hydrogen bonds with amino acids that also serve as Ca2+ ligands. The different stereochemistry of the 3- and 4-OH groups in mannose and galactose, combined with a fixed Ca2+ coordination geometry, leads to different pyranose ring locations in the two cases. The glycine-rich loop provides selectivity against mannose by holding a critical tryptophan in a position optimal for packing with the apolar face of galactose but incompatible with mannose binding. The 2-acetamido substituent of GalNAc is in the vicinity of amino acid positions identified by site-directed mutagenesis (Iobst, S. T., and Drickamer, K. (1996) J. Biol. Chem. 271, 6686-6693) as being important for the formation of a GalNAc-selective binding site. PubMed: 8636086DOI: 10.1074/jbc.271.12.6679 PDB entries with the same primary citation |
| Experimental method | X-RAY DIFFRACTION (1.9 Å) |
Structure validation
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