1dbn

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spinqualitylabelsall models 1dbn, resolution 2.75Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image

MAACKIA AMURENSIS LEUKOAGGLUTININ (LECTIN) WITH SIALYLLACTOSE

Overview

Seeds from the legume tree Maackia amurensis contain two lectins that can, agglutinate different blood cell types. Their specificity toward, sialylated oligosaccharides is unique among legume lectins; the, leukoagglutinin preferentially binds to sialyllactosamine, (alphaNeuAc(2-3)betaGal(1-4)betaGlcNAc), whereas the hemagglutinin, displays higher affinity for a disialylated tetrasaccharide, (alphaNeuAc(2-3)betaGal(1-3)[alphaNeuAc(2-6)]alphaG alNAc). The, three-dimensional structure of the complex between M. amurensis, leukoagglutinin and sialyllactose has been determined at 2.75-A resolution, using x-ray crystallography. The carbohydrate binding site consists of a, deep cleft that accommodates the three carbohydrate residues of the, sialyllactose. The central galactose sits in the primary binding site in, an orientation that has not been observed previously in other legume, lectins. The carboxyl group of sialic acid establishes a salt bridge with, a lysine side chain. The glucose residue is very efficiently docked, between two tyrosine aromatic rings. The complex between M. amurensis, hemagglutinin and a disialylated tetrasaccharide could be modeled from the, leukoagglutinin/sialyllactose crystal structure. The substitution of one, tyrosine by an alanine residue is responsible for the difference in fine, specificity between the two isolectins. Comparison with other legume, lectins indicates that oligosaccharide specificity within this family is, achieved by the recycling of structural loops in different combinations.

About this Structure

1DBN is a Single protein structure of sequence from Maackia amurensis with NAG, CA and MN as ligands. Full crystallographic information is available from OCA.

Reference

An unusual carbohydrate binding site revealed by the structures of two Maackia amurensis lectins complexed with sialic acid-containing oligosaccharides., Imberty A, Gautier C, Lescar J, Perez S, Wyns L, Loris R, J Biol Chem. 2000 Jun 9;275(23):17541-8. PMID:10747930

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