Abstract
Plant lectins, especially those purified from species of the Leguminosae family, represent the best-studied group of carbohydrate-binding proteins. Lectins purified from seeds of the Diocleinae subtribe exhibit a high degree of sequence identity notwithstanding that they show very distinct biological activities. Two main factors have been related to this feature: variance in key residues influencing the carbohydrate-binding site geometry and differences in the pH-dependent oligomeric state profile. In this work, we have isolated a lectin from Canavalia boliviana (Cbol) and solved its x-ray crystal structure in the unbound form and in complex with the carbohydrates Man(α1-3)Man(α1-O)Me, Man(α1-4)Man(α1-O)Me and 5-bromo-4-chloro-3-indolyl-α-D-mannose. We evaluated its oligomerization profile at different pH values using Small Angle X-ray Scattering and compared it to that of Concanavalin A. Based on predicted pKa-shifts of amino acids in the subunit interfaces we devised a model for the dimer-tetramer equilibrium phenomena of these proteins. Additionally, we demonstrated Cbol anti-inflammatory properties and further characterized them using in vivo and in vitro models.
Publication types
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Research Support, Non-U.S. Gov't
MeSH terms
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Amino Acid Sequence
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Animals
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Anti-Inflammatory Agents / pharmacology*
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Binding Sites
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Canavalia / chemistry*
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Cell Movement / drug effects
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Chemotaxis / drug effects
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Crystallography, X-Ray
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Edema / chemically induced
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Edema / drug therapy*
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Mannosides / chemistry*
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Mannosides / metabolism
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Models, Molecular
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Molecular Sequence Data
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Neutrophils / cytology
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Neutrophils / drug effects
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Peritonitis / chemically induced
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Peritonitis / drug therapy*
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Plant Lectins / chemistry*
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Plant Lectins / pharmacology*
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Protein Conformation
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Rats
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Rats, Wistar
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Seeds / chemistry*
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Sequence Homology, Amino Acid
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Spectrometry, Mass, Electrospray Ionization
Substances
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Anti-Inflammatory Agents
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Mannosides
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Plant Lectins
Grants and funding
This work is funded by Fundação Cearense de Apoio ao Desenvolvimento Científico e Tecnológico - FUNCAP, Conselho Nacional de Desenvolvimento Científico e Tecnológico - CNPq, Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES, National Synchrotron Light Laboratory - LNLS, Brazil. BSC is senior investigator of CNPq. Additional funding was provided by the Doktoratskolleg “Molecular Enzymology” Grant W901-B05 from the Austrian Science Fund (to KG and GAB). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.