Lectin cross-linking interactions with multivalent carbohydrates.
The present findings provide a molecular basis for a new paradigm of specificity in multivalent carbohydrate-lectin interactions, namely the formation of type 2 homogeneous cross-linked lattices between multivalent carbohydrates and lectins. The present x-ray data demonstrate that the cross-linked complexes formed between a series of structurally related divalent carbohydrates and a single tetravalent lectin (SBA) are distinct and due to crystal packing interactions. These results thus provide a molecular basis for the formation of homogeneous type 2 cross-linked complexes between lectins and multivalent carbohydrates and glycoconjugates. These findings are also relevant to the observations that lectin-carbohydrate cross-linking interactions are involved in cellular recognition and signal transduction processes. For example, activated human T-cells undergo apoptosis due to binding and cross-linking of specific glycoprotein receptors by galectin-1 (Pace et al., 1999). Confocal microscopy shows that the galectin cross-linked glycoprotein receptors form homogeneous aggregates from a population of previously dispersed molecules on the surface of the cells. The crystal structures of the four SBA/pentasaccharide complexes thus repesent models for lectin-carbohydrate clustering in vivo.
Brewer
C F
CF
Department of Molecular Pharmacology, Albert Einstein College of Medicine, Bronx, New York 10641, USA.
D000818:Animals; D050260:Carbohydrate Metabolism; D002240:Carbohydrate Sequence; D002241:Carbohydrates / Q000737:chemistry*; D003432:Cross-Linking Reagents; D018360:Crystallography, X-Ray; D004563:Electrochemistry; D066298:In Vitro Techniques; D037102:Lectins / Q000737:chemistry* / Q000378:metabolism*; D046911:Macromolecular Substances; D008958:Models, Molecular; D008969:Molecular Sequence Data; D009844:Oligosaccharides / Q000737:chemistry / Q000378:metabolism; D037121:Plant Lectins / Q000737:chemistry / Q000378:metabolism; D030262:Soybean Proteins / Q000737:chemistry / Q000378:metabolism; D010835:Phytohemagglutinins
D002241:Carbohydrates; D003432:Cross-Linking Reagents; D037102:Lectins; D046911:Macromolecular Substances; D009844:Oligosaccharides; D037121:Plant Lectins; D030262:Soybean Proteins; C028824:soybean lectin; D010835:Phytohemagglutinins