1QDC
MAN(APLHA1-6)MAN(ALPHA1-O)METHYL CONCANAVALIN A COMPLEX
Summary for 1QDC
| Entry DOI | 10.2210/pdb1qdc/pdb |
| Descriptor | PROTEIN (CONCANAVALIN A), alpha-D-mannopyranose-(1-6)-methyl alpha-D-mannopyranoside, MANGANESE (II) ION, ... (6 entities in total) |
| Functional Keywords | plant lectin, carbohydrate binding, dimannose, concanavalin a, sugar binding protein |
| Biological source | Canavalia ensiformis (jack bean) |
| Total number of polymer chains | 4 |
| Total formula weight | 104330.35 |
| Authors | Bouckaert, J.,Loris, R.,Wyns, L. (deposition date: 1998-07-14, release date: 1999-10-14, Last modification date: 2023-08-16) |
| Primary citation | Bouckaert, J.,Hamelryck, T.W.,Wyns, L.,Loris, R. The crystal structures of Man(alpha1-3)Man(alpha1-O)Me and Man(alpha1-6)Man(alpha1-O)Me in complex with concanavalin A. J.Biol.Chem., 274:29188-29195, 1999 Cited by PubMed Abstract: The crystal structures of concanavalin A in complex with Man(alpha1-6)Man(alpha1-O)Me and Man(alpha1-3)Man(alpha1-O)Me were determined at resolutions of 2.0 and 2.8 A, respectively. In both structures, the O-1-linked mannose binds in the conserved monosaccharide-binding site. The O-3-linked mannose of Man(alpha1-3)Man(alpha1-O)Me binds in the hydrophobic subsite formed by Tyr-12, Tyr-100, and Leu-99. The shielding of a hydrophobic surface is consistent with the associated large heat capacity change. The O-6-linked mannose of Man(alpha1-6)Man(alpha1-O)Me binds in the same subsite formed by Tyr-12 and Asp-16 as the reducing mannose of the highly specific trimannose Man(alpha1-3)[Man(alpha1-6)]Man(alpha1-O)Me. However, it is much less tightly bound. Its O-2 hydroxyl makes no hydrogen bond with the conserved water 1. Water 1 is present in all the sugar-containing concanavalin A structures and increases the complementarity between the protein-binding surface and the sugar, but is not necessarily a hydrogen-bonding partner. A water analysis of the carbohydrate-binding site revealed a conserved water molecule replacing O-4 on the alpha1-3-linked arm of the trimannose. No such water is found for the reducing or O-6-linked mannose. Our data indicate that the central mannose of Man(alpha1-3)[Man(alpha1-6)]Man(alpha1-O)Me primarily functions as a hinge between the two outer subsites. PubMed: 10506175DOI: 10.1074/jbc.274.41.29188 PDB entries with the same primary citation |
| Experimental method | X-RAY DIFFRACTION (2 Å) |
Structure validation
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