1ehh
CRYSTAL STRUCTURE OF URTICA DIOICA AGGLUTININ ISOLECTIN VI COMPLEX WITH TRI-N-ACETYLCHITOTRIOSE
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OverviewOverview
Urtica dioica agglutinin is a small plant lectin that binds chitin. We, purified the isolectin VI (UDA-VI) and crystal structures of the isolectin, and its complex with tri-N-acetylchitotriose (NAG3) were determined by, X-ray analysis. The UDA-VI consists of two domains analogous to hevein and, the backbone folding of each domain is maintained by four disulfide, bridges. The sequence similarity of the two domains is not high (42 %) but, their backbone structures are well superimposed except some loop regions., The chitin binding sites are located on the molecular surface at both ends, of the dumbbell-shape molecule. The crystal of the NAG3 complex contains, two independent molecules forming a protein-sugar 2:2 complex. One NAG3, molecule is sandwiched between two independent UDA-VI molecules and the, other sugar molecule is also sandwiched by one UDA-VI molecule and, symmetry-related another one. The sugar binding site of N-terminal domain, consists of three subsites accommodating NAG3 while two NAG residues are, bound to the C-terminal domain. In each sugar-binding site, three aromatic, amino acid residues and one serine residue participate to the NAG3, binding. The sugar rings bound to two subsites are stacked to the, side-chain groups of tryptophan or histidine and a tyrosine residue is in, face-to-face contact with an acetylamino group, to which the hydroxyl, group of a serine residue is hydrogen-bonded. The third subsite of the, N-terminal domain binds a NAG moiety with hydrogen bonds. The results, suggest that the triad of aromatic amino acid residues is intrinsic in, sugar binding of hevein-like domains.
About this StructureAbout this Structure
1EHH is a Single protein structure of sequence from Urtica dioica. Full crystallographic information is available from OCA.
ReferenceReference
Crystal structures of Urtica dioica agglutinin and its complex with tri-N-acetylchitotriose., Harata K, Muraki M, J Mol Biol. 2000 Mar 31;297(3):673-81. PMID:10731420
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