Structural basis of carbohydrate recognition by lectin II from Ulex europaeus, a protein with a promiscuous carbohydrate-binding site.

TitleStructural basis of carbohydrate recognition by lectin II from Ulex europaeus, a protein with a promiscuous carbohydrate-binding site.
Publication TypeJournal Article
Year of Publication2000
AuthorsLoris, R., H. De Greve, M. H. Dao-Thi, J. Messens, A. Imberty, and L. Wyns
JournalJ Mol Biol
Volume301
Issue4
Pagination987-1002
Date Published2000 Aug 25
ISSN0022-2836
KeywordsAmino Acid Sequence, Binding Sites, Carbohydrate Metabolism, Chitin, Cloning, Molecular, Crystallography, X-Ray, Disaccharides, Evolution, Molecular, Fabaceae, Galactose, Glycosylation, Hydrogen Bonding, Lactose, Lectins, Models, Molecular, Molecular Sequence Data, Oligosaccharides, Peptidylprolyl Isomerase, Plant Lectins, Plants, Medicinal, Protein Structure, Quaternary, Protein Structure, Secondary, Sequence Alignment, Substrate Specificity, Trisaccharides
Abstract

Protein-carbohydrate interactions are the language of choice for inter- cellular communication. The legume lectins form a large family of homologous proteins that exhibit a wide variety of carbohydrate specificities. The legume lectin family is therefore highly suitable as a model system to study the structural principles of protein-carbohydrate recognition. Until now, structural data are only available for two specificity families: Man/Glc and Gal/GalNAc. No structural data are available for any of the fucose or chitobiose specific lectins. The crystal structure of Ulex europaeus (UEA-II) is the first of a legume lectin belonging to the chitobiose specificity group. The complexes with N-acetylglucosamine, galactose and fucosylgalactose show a promiscuous primary binding site capable of accommodating both N-acetylglucos amine or galactose in the primary binding site. The hydrogen bonding network in these complexes can be considered suboptimal, in agreement with the low affinities of these sugars. In the complexes with chitobiose, lactose and fucosyllactose this suboptimal hydrogen bonding network is compensated by extensive hydrophobic interactions in a Glc/GlcNAc binding subsite. UEA-II thus forms the first example of a legume lectin with a promiscuous binding site and illustrates the importance of hydrophobic interactions in protein-carbohydrate complexes. Together with other known legume lectin crystal structures, it shows how different specificities can be grafted upon a conserved structural framework.

DOI10.1006/jmbi.2000.4016
Alternate JournalJ. Mol. Biol.
PubMed ID10966800
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