title: The carbohydrate-binding promiscuity of Euonymus europaeus lectin is predicted to involve a single binding site.
abstract: Euonymus europaeus lectin (EEL) is a carbohydrate-binding protein derived from the fruit of the European spindle tree. EEL was first identified for its erythrocyte agglutinating properties and specificity for B and H blood groups. However, a detailed molecular picture of the structural basis of carbohydrate recognition by EEL remains to be developed. In this study, we performed fluorescence titrations of a range of carbohydrates against EEL. Binding of EEL to a wide range of carbohydrates was observed, including a series of blood group-related carbohydrates, mannosides, chitotriose and sialic acid. Affinity was strongest for carbohydrates with H-related structures and the B trisaccharide. A homology model of EEL was produced from templates identified using the HHPred server, which employs hidden Markov models (HMMs) to identify templates. The HMM approach identified that the best templates for EEL were proteins featuring a ricin B-like (R-type) fold. Separate templates were used to model the core and binding site regions of the lectin. Through the use of constrained docking and spatial comparison with a template ligand, binding modes for the carbohydrate ligands were predicted. A relationship between the experimental binding energies and the computed binding energies of the selected docked poses was determined and optimized. Collectively, our results suggest that EEL utilizes a single site for recognition of carbohydrates terminating in a variety of monosaccharides.
authors.affiliation: School of Biomedical Sciences, CHIRI Biosciences, Curtin University, Perth, WA 6845, Australia Joint BSC-IRB Research Program in Computational Biology, Life Science Department, Barcelona Supercomputing Centre, Barcelona 08034, Spain Centre for Biomedical Research, Burnet Institute, Melbourne, VIC 3004, Australia Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, VIC 3052, Australia.
authors.forename: Mark
authors.initials: M
authors.lastname: Agostino
authors.affiliation: Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, VIC 3052, Australia.
authors.forename: Tony
authors.initials: T
authors.lastname: Velkov
authors.affiliation: Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, VIC 3052, Australia.
authors.forename: Tamir
authors.initials: T
authors.lastname: Dingjan
authors.affiliation: School of Chemistry and Bio21 Molecular Science and Biotechnology Institute, University of Melbourne, Parkville, VIC 3010, Australia.
authors.forename: Spencer J
authors.initials: SJ
authors.lastname: Williams
authors.affiliation: Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, VIC 3052, Australia pramsland@burnet.edu.au elizabeth.yuriev@monash.edu.
authors.forename: Elizabeth
authors.initials: E
authors.lastname: Yuriev
authors.affiliation: School of Biomedical Sciences, CHIRI Biosciences, Curtin University, Perth, WA 6845, Australia Centre for Biomedical Research, Burnet Institute, Melbourne, VIC 3004, Australia Department of Surgery Austin Health, University of Melbourne, Heidelberg, VIC 3084, Australia Department of Immunology, Alfred Medical Research and Education Precinct, Monash University, Melbourne, VIC 3004, Australia pramsland@burnet.edu.au elizabeth.yuriev@monash.edu.
authors.forename: Paul A
authors.initials: PA
authors.lastname: Ramsland
mesh_terms: D000595:Amino Acid Sequence; D023181:Antimicrobial Cationic Peptides / Q000737:chemistry* / Q000302:isolation & purification; D001665:Binding Sites; D001789:Blood Group Antigens / Q000737:chemistry*; D002236:Carbohydrate Conformation; D002240:Carbohydrate Sequence; D029756:Euonymus / Q000737:chemistry*; D007700:Kinetics; D008024:Ligands; D008362:Mannosides / Q000737:chemistry; D008390:Markov Chains; D062105:Molecular Docking Simulation; D008969:Molecular Sequence Data; D037121:Plant Lectins / Q000737:chemistry* / Q000302:isolation & purification; D011485:Protein Binding; D017510:Protein Folding; D012276:Ricin / Q000737:chemistry; D012794:Sialic Acids / Q000737:chemistry; D013050:Spectrometry, Fluorescence; D040681:Structural Homology, Protein; D013816:Thermodynamics; D014312:Trisaccharides / Q000737:chemistry
chemical_list: D023181:Antimicrobial Cationic Peptides; D001789:Blood Group Antigens; C047161:Evonymous europa lectin; D008024:Ligands; D008362:Mannosides; D037121:Plant Lectins; D012794:Sialic Acids; D014312:Trisaccharides; C041161:chitotriose; D012276:Ricin
keywords: Euonymus europaeus lectin; blood group carbohydrates; carbohydrate recognition; molecular docking; protein–carbohydrate interactions