Mannose-binding plant lectins: different structural scaffolds for a common sugar-recognition process.
Mannose-specific lectins are widely distributed in higher plants and are believed to play a role in recognition of high-mannose type glycans of foreign micro-organisms or plant predators. Structural studies have demonstrated that the mannose-binding specificity of lectins is mediated by distinct structural scaffolds. The mannose/glucose-specific legume (e.g., Con A, pea lectin) exhibit the canonical twelve-stranded beta-sandwich structure. In contrast to legume lectins that interact with both mannose and glucose, the monocot mannose-binding lectins (e.g., the Galanthus nivalis agglutinin or GNA from bulbs) react exclusively with mannose and mannose-containing N-glycans. These lectins possess a beta-prism structure. More recently, an increasing number of mannose-specific lectins structurally related to jacalin (e.g., the lectins from the Jerusalem artichoke, banana or rice), which also exhibit a beta-prism organization, were characterized. Jacalin itself was re-defined as a polyspecific lectin which, in addition to galactose, also interacts with mannose and mannose-containing glycans. Finally the B-chain of the type II RIP of iris, which has the same beta-prism structure as all other members of the ricin-B family, interacts specifically with mannose and galactose. This structural diversity associated with the specific recognition of high-mannose type glycans highlights the importance of mannose-specific lectins as recognition molecules in higher plants.
Barre
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A
Institut de Pharmacologie et de Biologie Structurale, UMR-CNRS 5089, 205, route de Narbonne, 31077 Toulouse cedex 4, France.
Bourne
Y
Y
Van Damme
E J
EJ
Peumans
W J
WJ
Rougé
P
P
D001665:Binding Sites; D002352:Carrier Proteins / Q000737:chemistry; D037222:Collectins; D005690:Galactose / Q000378:metabolism; D005947:Glucose / Q000378:metabolism; D037102:Lectins / Q000737:chemistry / Q000378:metabolism*; D008358:Mannose / Q000378:metabolism*; D008958:Models, Molecular; D009699:N-Glycosyl Hydrolases / Q000378:metabolism*; D037121:Plant Lectins; D010940:Plant Proteins / Q000378:metabolism*; D010944:Plants; D011485:Protein Binding; D020836:Protein Structure, Quaternary; D017433:Protein Structure, Secondary; D017434:Protein Structure, Tertiary; D054790:Ribosome Inactivating Proteins, Type 2
D002352:Carrier Proteins; D037222:Collectins; D037102:Lectins; D037121:Plant Lectins; D010940:Plant Proteins; D054790:Ribosome Inactivating Proteins, Type 2; C043696:jacalin; D009699:N-Glycosyl Hydrolases; D005947:Glucose; D008358:Mannose; D005690:Galactose