1npl
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MANNOSE-SPECIFIC AGGLUTININ (LECTIN) FROM DAFFODIL (NARCISSUS PSEUDONARCISSUS) BULBS IN COMPLEX WITH MANNOSE-ALPHA1,3-MANNOSE
OverviewOverview
Carbohydrate recognition by monocot mannose-binding lectins was studied, via the crystal structure determination of daffodil (Narcissus, pseudonarcissus) lectin. The lectin was extracted from daffodil bulbs, and, crystallised in the presence of alpha-1,3 mannobiose. Molecular, replacement methods were used to solve the structure using the partially, refined model of Hippeastrum hybrid agglutinin as a search model. The, structure was refined at 2.0 A resolution to a final R -factor of 18.7 %, and Rfreeof 26.7 %.The main feature of the daffodil lectin structure is, the presence of three fully occupied binding pockets per monomer, arranged, around the faces of a triangular beta-prism motif. The pockets have, identical topology, and can bind mono-, di- or oligosaccharides. Strand, exchange forms tightly bound dimers, and higher aggregation states are, achieved through hydrophobic patches on the surface, completing a tetramer, with internal 222-symmetry. There are therefore 12 fully occupied binding, pockets per tetrameric cluster. The tetramer persists in solution, as, shown with small-angle X-ray solution scattering. Extensive sideways and, out-of-plane interactions between tetramers, some mediated via the ligand, make up the bulk of the lattice contacts.A fourth binding site was also, observed. This is unique and has not been observed in similar structures., The site is only partially occupied by a ligand molecule due to the much, lower binding affinity. A comparison with the Galanthus nivalis, agglutinin/mannopentaose complex suggests an involvement of this site in, the recognition mechanism for naturally occurring glycans.
About this StructureAbout this Structure
1NPL is a Single protein structure of sequence from Narcissus pseudonarcissus with PO4 as ligand. Full crystallographic information is available from OCA.
ReferenceReference
Insights into carbohydrate recognition by Narcissus pseudonarcissus lectin: the crystal structure at 2 A resolution in complex with alpha1-3 mannobiose., Sauerborn MK, Wright LM, Reynolds CD, Grossmann JG, Rizkallah PJ, J Mol Biol. 1999 Jul 2;290(1):185-99. PMID:10388566
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