High-resolution crystal structures of Erythrina cristagalli lectin in complex with lactose and 2'-alpha-L-fucosyllactose and correlation with thermodynamic binding data.
The primary sequence of Erythrina cristagalli lectin (ECL) was mapped by mass spectrometry, and the crystal structures of the lectin in complex with lactose and 2'-alpha-L-fucosyllactose were determined at 1.6A and 1.7A resolution, respectively. The two complexes were compared with the crystal structure of the closely related Erythrina corallodendron lectin (ECorL) in complex with lactose, with the crystal structure of the Ulex europaeus lectin II in complex with 2'-alpha-L-fucosyllactose, and with two modeled complexes of ECorL with 2'-alpha-L-fucosyl-N-acetyllactosamine. The molecular models are very similar to the crystal structure of ECL in complex with 2'-alpha-L-fucosyllactose with respect to the overall mode of binding, with the L-fucose fitting snugly into the cavity surrounded by Tyr106, Tyr108, Trp135 and Pro134 adjoining the primary combining site of the lectin. Marked differences were however noted between the models and the experimental structure in the network of hydrogen bonds and hydrophobic interactions holding the L-fucose in the combining site of the lectin, pointing to limitations of the modeling approach. In addition to the structural characterization of the ECL complexes, an effort was undertaken to correlate the structural data with thermodynamic data obtained from microcalorimetry, revealing the importance of the water network in the lectin combining site for carbohydrate binding.
Department of Molecular Biotechnology and Center for Structural Biology, Chalmers University of Technology, P. O. Box 462, SE-405-30 Goteborg, Sweden.
Cecilia
C
Svensson
Susann
S
Teneberg
Carol L
CL
Nilsson
Anders
A
Kjellberg
Frederick P
FP
Schwarz
Nathan
N
Sharon
Ute
U
Krengel
D000595:Amino Acid Sequence; D019943:Amino Acid Substitution; D001665:Binding Sites; D002151:Calorimetry; D002240:Carbohydrate Sequence; D018360:Crystallography, X-Ray; D004895:Erythrina / Q000737:chemistry*; D006031:Glycosylation; D006860:Hydrogen Bonding; D057927:Hydrophobic and Hydrophilic Interactions; D007785:Lactose / Q000737:chemistry / Q000378:metabolism*; D037102:Lectins / Q000737:chemistry* / Q000378:metabolism*; D008958:Models, Molecular; D008969:Molecular Sequence Data; D010449:Peptide Mapping; D037121:Plant Lectins; D011485:Protein Binding; D020836:Protein Structure, Quaternary; D017434:Protein Structure, Tertiary; D012680:Sensitivity and Specificity; D016415:Sequence Alignment; D013816:Thermodynamics; D014312:Trisaccharides / Q000737:chemistry / Q000378:metabolism*; D014867:Water / Q000737:chemistry / Q000378:metabolism
D037102:Lectins; D037121:Plant Lectins; D014312:Trisaccharides; D014867:Water; D007785:Lactose; C031420:2'-fucosyllactose