title: High affinity fucose binding of Pseudomonas aeruginosa lectin PA-IIL: 1.0 A resolution crystal structure of the complex combined with thermodynamics and computational chemistry approaches.
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.
authors.affiliation: E.S.R.F. Experiments Division, Grenoble, France.
authors.forename: Edward P
authors.initials: EP
authors.lastname: Mitchell
authors.forename: Charles
authors.initials: C
authors.lastname: Sabin
authors.forename: Lenka
authors.initials: L
authors.lastname: Snajdrová
authors.forename: Martina
authors.initials: M
authors.lastname: Pokorná
authors.forename: Stéphanie
authors.initials: S
authors.lastname: Perret
authors.forename: Catherine
authors.initials: C
authors.lastname: Gautier
authors.forename: Ctirad
authors.initials: C
authors.lastname: Hofr
authors.forename: Nechama
authors.initials: N
authors.lastname: Gilboa-Garber
authors.forename: Jaroslav
authors.initials: J
authors.lastname: Koca
authors.forename: Michaela
authors.initials: M
authors.lastname: Wimmerová
authors.forename: Anne
authors.initials: A
authors.lastname: Imberty
mesh_terms: D018829:Adhesins, Bacterial / Q000737:chemistry*; D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000737:chemistry; D001665:Binding Sites; D002118:Calcium / Q000737:chemistry; D002151:Calorimetry; D002241:Carbohydrates / Q000737:chemistry; D019295:Computational Biology / Q000379:methods*; D018360:Crystallography, X-Ray / Q000379:methods*; D003550:Cystic Fibrosis / Q000378:metabolism; D004926:Escherichia coli / Q000378:metabolism; D005643:Fucose / Q000737:chemistry*; D006388:Hemagglutinins / Q000378:metabolism; D006358:Hot Temperature; D006860:Hydrogen Bonding; D006863:Hydrogen-Ion Concentration; D007477:Ions; D037102:Lectins / Q000737:chemistry*; D008024:Ligands; D008958:Models, Molecular; D008968:Molecular Conformation; D008969:Molecular Sequence Data; D010957:Plasmids / Q000378:metabolism; D011485:Protein Binding; D011506:Proteins / Q000737:chemistry; D011522:Protons; D011550:Pseudomonas aeruginosa / Q000378:metabolism*; D011994:Recombinant Proteins / Q000737:chemistry; D012984:Software; D013696:Temperature; D013816:Thermodynamics
chemical_list: D018829:Adhesins, Bacterial; D001426:Bacterial Proteins; D002241:Carbohydrates; D006388:Hemagglutinins; D007477:Ions; D037102:Lectins; D008024:Ligands; D011506:Proteins; D011522:Protons; D011994:Recombinant Proteins; C038692:adhesin, Pseudomonas; C027112:fucose-binding lectin; D005643:Fucose; D002118:Calcium