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spinqualitylabelsall models 1rin, resolution 2.6Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image

X-RAY CRYSTAL STRUCTURE OF A PEA LECTIN-TRIMANNOSIDE COMPLEX AT 2.6 ANGSTROMS RESOLUTION

Overview

The x-ray crystal structure of pea lectin, in complex with a methyl, glycoside of the N-linked-type oligosaccharide trimannosyl core, methyl, 3,6-di-O-(alpha-D-mannopyranosyl)-alpha-D-mannopyranoside, has been solved, by molecular replacement and refined at 2.6-A resolution. The R factor is, 0.183 for all data in the 8.0 to 2.6 A resolution range with an average, atomic temperature factor of 26.1 A2. Strong electron density for a single, mannose residue is found in the monosaccharide-binding site suggesting, that the trisaccharide binds primarily through one of the terminal, alpha-linked mannose residues. The complex is stabilized by hydrogen bonds, involving the protein residues Asp-81, Gly-99, Asn-125, Ala-217, and, Glu-218, and the carbohydrate oxygen atoms O3, O4, O5, and O6. In, addition, the carbohydrate makes van der Waals contacts with the protein, involving Phe-123 in particular. These interactions are very similar to, those found in the monosaccharide complexes with concanavalin A and, isolectin 1 of Lathyrus ochrus, confirming the structural relatedness of, this family of proteins. Comparison of the pea lectin complex with the, unliganded pea lectin and concanavalin A structures indicates differences, in the conformation and water structure of the unliganded binding sites of, these two proteins. Furthermore, a correlation between the position of the, carbohydrate oxygen atoms in the complex and the bound water molecules in, the unliganded binding sites is found. Binding of the trimannose core, through a single terminal monosaccharide residue strongly argues that an, additional fucose-binding site is responsible for the high affinity pea, lectin-oligosaccharide interactions.

About this Structure

1RIN is a Protein complex structure of sequences from Pisum sativum with MAN, MN and CA as ligands. Full crystallographic information is available from OCA.

Reference

X-ray crystal structure of a pea lectin-trimannoside complex at 2.6 A resolution., Rini JM, Hardman KD, Einspahr H, Suddath FL, Carver JP, J Biol Chem. 1993 May 15;268(14):10126-32. PMID:8486683

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