Novel Family of Lectins Evolutionarily Related to Class V Chitinases: An Example of Neofunctionalization in Legumes

• Published in: Plant physiology (Bethesda) 2007-06, Vol.144 (2), p.662-672
• Main Authors: Van Damme, Els J.M, Culerrier, Raphaël, Barre, Annick, Alvarez, Richard, Rougé, Pierre, Peumans, Willy J
• Format: Article
• Language: English
• Subjects: Agglutinins; Amino Acid Sequence; Amino acids; Bark; Biological and medical sciences; Biological Evolution; Carbohydrate Metabolism; Chitin; Chitinases - chemistry; Chitinases - metabolism; Cloning, Molecular; Evolution; Focus Issue on Legume Biology; Fundamental and applied biological sciences. Psychology; Glycine max; Lectins; Legumes; Lotus japonicus; Medicago truncatula; Models, Molecular; Molecular Sequence Data; Multigene Family; Nicotiana - chemistry; Nicotiana - enzymology; Parasitism and symbiosis; Plant Bark - chemistry; Plant Bark - metabolism; Plant Lectins - chemistry; Plant Lectins - genetics; Plant Lectins - metabolism; Plant physiology and development; Plants; Polysaccharides; Proteins; Robinia - chemistry; Robinia - genetics; Robinia - metabolism; Robinia pseudoacacia; Sequence Homology, Amino Acid; Symbiosis
• ISSN: 0032-0889; 1532-2548; 1532-2548
• DOI: 10.1104/pp.106.087981

A lectin has been identified in black locust (Robinia pseudoacacia) bark that shares approximately 50% sequence identity with plant class V chitinases but is essentially devoid of chitinase activity. Specificity studies indicated that the black locust chitinase-related agglutinin (RobpsCRA) preferentially binds to high-mannose N-glycans comprising the proximal pentasaccharide core structure. Closely related orthologs of RobpsCRA could be identified in the legumes Glycine max, Medicago truncatula, and Lotus japonicus but in no other plant species, suggesting that this novel lectin family most probably evolved in an ancient legume species or possibly an earlier ancestor. This identification of RobpsCRA not only illustrates neofunctionalization in plants, but also provides firm evidence that plants are capable of developing a sugar-binding domain from an existing structural scaffold with a different activity and accordingly sheds new light on the molecular evolution of plant lectins.