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.
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.
Mitchell
Edward P
EP
E.S.R.F. Experiments Division, Grenoble, France.
Sabin
Charles
C
Snajdrová
Lenka
L
Pokorná
Martina
M
Perret
Stéphanie
S
Gautier
Catherine
C
Hofr
Ctirad
C
Gilboa-Garber
Nechama
N
Koca
Jaroslav
J
Wimmerová
Michaela
M
Imberty
Anne
A
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
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