Showing papers by "Anne Imberty published in 2004"
TL;DR: The structural aspects of PA-IL adn PA-IIL relative to their putative roles in host recognition, cell surface adhesion and biofilm formation are reviewed.
301 citations
TL;DR: It is reported here that heparin and HS specifically prevent the processing of SDF-1 by DPP IV expressed by Caco-2 cells, and it is found that protection depends on the degree of polymerization of the HS sulfated S-domains.
203 citations
TL;DR: The addition of ZnCl2 to endostatin enhanced its binding to heparin and heparan sulfate by ∼40% as well as its antiproliferative effect on endothelial cells stimulated by fibroblast growth factor-2, suggesting that this activity is mediated by the binding ofendostatin to he parin andHeparin sulfate.
136 citations
TL;DR: Mutational analysis showed that residues His299 and Tyr300 of the new motif, and His316 of the VS motif, are essential for activity since their substitution by alanine yielded inactive enzymes, and the invariant Tyr residue plays an important conformational role mainly attributable to the aromatic ring.
118 citations
TL;DR: Calculations of partial charges indicated that extensive delocalization of charges between the calcium ions, the side chains of the protein‐binding site and the carbohydrate ligand is responsible for the high enthalpy of binding and therefore for the unusually high affinity observed for this unique mode of carbohydrate recognition.
Abstract: PA-IIL is a fucose-binding lectin from Pseudomonas aeruginosa that is closely related to the virulence factors of the bacterium. Previous structural studies have revealed a new carbohydrate-binding mode with direct involvement of two calcium ions (Mitchell E, Houles C, Sudakevitz D, Wimmerova M, Gautier C, Perez S, Wu AM, Gilboa-Garber N, Imberty A. Structural basis for selective recognition of oligosaccharides from cystic fibrosis patients by the lectin PA-IIL of Pseudomonas aeruginosa. Nat Struct Biol 2002;9:918-921). A combination of thermodynamic, structural, and computational methods has been used to study the basis of the high affinity for the monosaccharide ligand. A titration microcalorimetry study indicated that the high affinity is enthalpy driven. The crystal structure of the tetrameric PA-IIL in complex with fucose and calcium was refined to 1.0 A resolution and, in combination with modeling, allowed a proposal to be made for the hydrogen-bond network in the binding site. Calculations of partial charges using ab initio computational chemistry methods indicated that extensive delocalization of charges between the calcium ions, the side chains of the protein-binding site and the carbohydrate ligand is responsible for the high enthalpy of binding and therefore for the unusually high affinity observed for this unique mode of carbohydrate recognition.
108 citations
TL;DR: It is reported that L-SIGN, a highly related homologue of DC-SIGN found on liver sinusoidal endothelial cells, binds to S. mansoni egg antigens but not to the Lex epitope, and indicates that Val351 is important for the fucose specificity ofDC-SIGN.
104 citations
TL;DR: The plant pathogen Ralstonia solanacearum produces two lectins, each with different affinity to fucose, and the discovery of RS‐IIL, a tetrameric lectin, with high sequence similarity to the fucOSE‐binding lectin PA‐ IIL of Pseudomonas aeruginosa is reported.
Abstract: The plant pathogen Ralstonia solanacearum produces two lectins, each with different affinity to fucose. We described previously the properties and sequence of the first lectin, RSL (subunit M(r) 9.9 kDa), which is related to fungal lectins (Sudakevitz, D., Imberty, A., and Gilboa-Garber, N., 2002, J Biochem 132: 353-358). The present communication reports the discovery of the second one, RS-IIL (subunit M(r) 11.6 kDa), a tetrameric lectin, with high sequence similarity to the fucose-binding lectin PA-IIL of Pseudomonas aeruginosa. RS-IIL recognizes fucose but displays much higher affinity to mannose and fructose, which is opposite to the preference spectrum of PA-IIL. Determination of the crystal structure of RS-IIL complexed with a mannose derivative demonstrates a tetrameric structure very similar to the recently solved PA-IIL structure (Mitchell, E., et al., 2002, Nature Struct Biol 9: 918-921). Each monomer contains two close calcium cations that mediate the binding of the monosaccharide and explain the outstandingly high affinity to the monosaccharide ligand. The binding loop of the cations is fully conserved in RS-IIL and PA-IIL, whereas the preference for mannose versus fucose can be attributed to the change of a three-amino-acid sequence in the 'specificity loop'.
75 citations
26 citations
TL;DR: Analysis of the structural water molecules location confirmed that the mobility of water molecules in the active site and the accessibility of this site for solvent are higher in the absence of the substrate.
13 citations
Journal Article•
TL;DR: The present communication reports the discovery of RS-IIL, a tetrameric lectin, with high sequence similarity to the fucose-binding lectin PA- IIL of Pseudomanas aeruginosa, which recognizes fucOSE but displays much higher affinity to mannose and fructose, which is opposite to the preference spectrum of PA-iiL.
Abstract: The plant pathogen Ralstonia solanacearum produces two lectins,
each with different affinity for fucose. We described
previously the properties and sequence of the first lectin, RSL
(subunit Mr 9.9 kDa), that is related to fungal lectins
(Sudakevitz, D., Imberty, A., and Gilboa-Garber, N. (2002) J.
Biochem. 132: 353-358). The present communication reports the
discovery of the second one, RS-IIL (subunit Mr 11.6 kDa), a
tetrameric lectin, with high sequence similarity to the
fucose-binding lectin PA-IIL of Pseudomanas aeruginosa. RS-IIL
recognizes fucose but displays much higher affinity to mannose
and fructose, which is opposite to the preference spectrum of
PA-IIL. Determination of the crystal structure of RS-IIL
complexed with a mannose derivative demonstrates a tetrameric
structure very similar to the recently solved PA-IIL structure
(Mitchell et al. (2002) Nature Struct. Biol. 9: 918-921). Each
monomer contains two close calcium cations which mediate the
binding of the monosaccharide and explain the outstandingly
high affinity to the monosaccharide ligand. The binding loop of
the cations is fully conserved in RS-IIL and PA-IIL while the
preference for mannose versus fucose can be attributed to the
change of a three amino acids sequence in the specificity loop.
2 citations
TL;DR: In this article, a rat liver α-2,6-sialyltransferase (ST6GalI) or recombinant human fucosyltansferase V (FucT-V) was used to give conformationally constrained trisaccharides 5 and 6, respectively.
Abstract: N-Acetyllactosamine derivative 4, which has a methylene amide tether between C-6 and C-2′, was enzymatically glycosylated using rat liver α-2,6-sialyltransferase (ST6GalI) or recombinant human fucosyltansferase V (FucT-V) to give conformationally constrained trisaccharides 5 and 6, respectively. The methylene amide linker of 4 was installed by a two-step procedure, which involved acylation of a C-6 amino function of a LacNAc derivative with chloroacetic anhydride followed by macrocyclization by nucleophilic displacement of the chloride by a C-2′ hydroxyl. The conformational properties of 4 were determined by a combination of NOE and trans-glycosidic heteronuclear coupling constant measurements and molecular mechanics simulations and these studies established that the glycosidic linkage of 4 is conformationally constrained and resides in only one of the several energy minima accessible to LacNAc. The apparent kinetic parameters of transfer to LacNAc and conformationally constrained saccharides 3 and 4 indicates that fucosyltransferase V recognize LacNAc in its A-conformer whereas α-2,6-sialyltransferase recongizes the B-conformer of LacNAc.
TL;DR: In this article, the seven-membered phostone arising from the attack of reagents on the acetal protecting group was obtained by treatment of methyl 2,3-di-O-benzyl-4,6-O-, 6-O,bensylidene-α(β)-d -glucopyranoside with triethyl phosphite and trimethylsilyl trifluoromethanesulfonate.
Abstract: Treatment of methyl 2,3-di-O-benzyl-4,6-O-benzylidene-α(β)- d -glucopyranoside with triethyl phosphite and trimethylsilyl trifluoromethanesulfonate affords the seven-membered phostone arising from the attack of reagents on the acetal protecting group.
TL;DR: The title compound, C6H8N2O3S2·H2O, was synthesized from l-erythrulose and the structure of the enantiopure (4R,9S) diastereo-isomer has been determined as mentioned in this paper.
Abstract: The title compound, C6H8N2O3S2·H2O, was synthesized from l-erythrulose and the structure of the enantiopure (4R,9S) diastereoisomer has been determined. The structure is a hydrate and the water molecules establish a hydrogen-bond network that involves the hydroxymethyl group as well as one N and one S atom.
TL;DR: Pseudomonas aeruginosa is essentially a saprophytic bacterium that can turn into an aggressive pathogen when in contact with damaged and inflamed tissues such as burns and lungs of cystic fibrosis patients.
Abstract: Pseudomonas aeruginosa is essentially a saprophytic bacterium that can turn into an aggressive pathogen when in contact with damaged and inflamed tissues such as burns and lungs of cystic fibrosis (CF) patients. In all of these cases, the host cell surfaces present altered glycosylations. The most studied example is that of CF where point mutations in the cystic fibrosis transmembrane conductance regulator (CFTR) gene, results in altered ion movements and also influences the N-glycosylation of the CFTR protein and other cell surface glycoproteins. Increased fucosylation and decreased sialylation with higher levels of Lewis x and Lewis a epitopes correlate to P. aeruginosa-specific binding. In addition, both the mucus covering the airway epithelia of CF patients and their salivary mucins display higher levels of sialylated and sulfated Lewis oligosaccharides that attract P. aeruginosa.