2vxj

CRYSTAL STRUCTURE OF PA-IL LECTIN COMPLEXED WITH AGAL13BGAL14GLC AT 1.9 A RESOLUTION

spinqualitylabelsall models 2vxj, resolution 1.90Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 2vxj is a 24 chain structure with sequence from Pseudomonas aeruginosa PAO1. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Method: X-ray diffraction, Resolution 1.9Å Ligands: BGC, CA, EDO, GAL, GLA, GLC Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Function PA1L_PSEAE D-galactose specific lectin. Binds in decreasing order of affinity: melibiose, methyl-alpha-D-galactoside, D-galactose, methyl-beta-D-galactoside, N-acetyl-D-galactosamine. Similar to plant lectins in its selective (carbohydrate-specific) hemagglutinating activity. Publication Abstract from PubMed The opportunistic pathogen Pseudomonas aeruginosa contains several carbohydrate-binding proteins, among which is the P. aeruginosa lectin I (PA-IL) lectin, which displays affinity for alpha-galactosylated glycans. Glycan arrays were screened and demonstrated stronger binding of PA-IL toward alphaGal1-4betaGal-terminating structures and weaker binding to alphaGal1-3betaGal ones in order to determine which human glycoconjugates could play a role in the carbohydrate-mediated adhesion of the bacteria. This was confirmed in vivo by testing the binding of the lectin to Burkitt lymphoma cells that present large amounts of globotriaosylceramide antigen Gb3/CD77/P(k). Trisaccharide moieties of Gb3 (alphaGal1-4betaGal1-4Glc) and isoglobotriaosylceramide (alphaGal1-3betaGal1-4Glc) were tested by titration microcalorimetry, and both displayed similar affinity to PA-IL in solution. The crystal structure of PA-IL complexed to alphaGal1-3betaGal1-4Glc trisaccharide has been solved at 1.9-A resolution and revealed how the second galactose residue makes specific contacts with the protein surface. Molecular modeling studies were performed in order to compare the binding mode of PA-IL toward alphaGal1-3Gal with that toward alphaGal1-4Gal. Docking studies demonstrated that alphaGal1-4Gal creates another network of contacts for achieving a very similar affinity, and 20-ns molecular dynamics in explicit water allowed for analyzing the flexibility of each disaccharide ligand in the protein binding site. The higher affinity observed for binding to Gb3 epitope, both in vivo and on glycan array, is likely related to the presentation effect of the oligosaccharide on a surface, since only the Gb3 glycosphingolipid geometry is fully compatible with parallel insertion of neighboring trisaccharide heads in two binding sites of the same tetramer of PA-IL. Structural Basis of the Preferential Binding for Globo-Series Glycosphingolipids Displayed by Pseudomonas aeruginosa Lectin I.,Blanchard B, Nurisso A, Hollville E, Tetaud C, Wiels J, Pokorna M, Wimmerova M, Varrot A, Imberty A J Mol Biol. 2008 Aug 22. PMID:18762193 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See Also Galactose-binding lectin

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