Bivalent Carbohydrate Binding Is Required for Biological Activity of Clitocybe nebularis Lectin (CNL), the N,N′-Diacetyllactosediamine (GalNAcβ1–4GlcNAc, LacdiNAc)-specific Lectin from Basidiomycete C. nebularis
| Autor: | Borut Štrukelj, David F. Smith, Dušan Turk, Jure Pohleven, Janko Kos, Miha Renko, Špela Magister, Markus Künzler, Jerica Sabotič |
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| Rok vydání: | 2012 |
| Předmět: |
Glycan
Erythrocytes Molecular Sequence Data Mutant Glycobiology and Extracellular Matrices Lactose Ricin Plasma protein binding Crystallography X-Ray Biochemistry ABO Blood-Group System Jurkat Cells 03 medical and health sciences chemistry.chemical_compound C-type lectin Escherichia coli Animals Humans Amino Acid Sequence Caenorhabditis elegans Protein Structure Quaternary Molecular Biology 030304 developmental biology 0303 health sciences biology 030302 biochemistry & molecular biology Lectin Biological activity Cell Biology biology.organism_classification Molecular biology Recombinant Proteins chemistry Mutation biology.protein Protein Multimerization Agaricales Protein Binding Clitocybe nebularis |
| Zdroj: | The Journal of biological chemistry |
| ISSN: | 0021-9258 |
| DOI: | 10.1074/jbc.m111.317263 |
| Popis: | Lectins are carbohydrate-binding proteins that exert their biological activity by binding to specific cell glycoreceptors. We have expressed CNL, a ricin B-like lectin from the basidiomycete Clitocybe nebularis in Escherichia coli. The recombinant lectin, rCNL, agglutinates human blood group A erythrocytes and is specific for the unique glycan N,N'-diacetyllactosediamine (GalNAcβ1-4GlcNAc, LacdiNAc) as demonstrated by glycan microarray analysis. We here describe the crystal structures of rCNL in complex with lactose and LacdiNAc, defining its interactions with the sugars. CNL is a homodimeric lectin, each of whose monomers consist of a single ricin B lectin domain with its β-trefoil fold and one carbohydrate-binding site. To study the mode of CNL action, a nonsugar-binding mutant and nondimerizing monovalent CNL mutants that retain carbohydrate-binding activity were prepared. rCNL and the mutants were examined for their biological activities against Jurkat human leukemic T cells and the hypersensitive nematode Caenorhabditis elegans mutant strain pmk-1. rCNL was toxic against both, although the mutants were inactive. Thus, the bivalent carbohydrate-binding property of homodimeric CNL is essential for its activity, providing one of the rare pieces of evidence that certain activities of lectins are associated with their multivalency. |
| Databáze: | OpenAIRE |
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