Related lectins from snowdrop and maize differ in their carbohydrate-binding specificity.
Searches in an EST database from maize revealed the expression of a protein related to the Galanthus nivalis (GNA) agglutinin, referred to as GNA(maize). Heterologous expression of GNA(maize) in Pichia pastoris allowed characterization of the first nucleocytoplasmic GNA homolog from plants. GNA(maize) is a tetrameric protein which shares 64% sequence similarity with GNA. Glycan microarray analyses revealed important differences in the specificity. Unlike GNA, which binds strongly to high-mannose N-glycans, the lectin from maize reacts almost exclusively with more complex glycans. Interestingly, GNA(maize) prefers complex glycans containing beta1-2 GlcNAc residues. The obvious difference in carbohydrate-binding properties is accompanied by a 100-fold reduced anti-HIV activity. Although the sequences of GNA and GNA(maize) are clearly related they show only 28% sequence identity. Our results indicate that gene divergence within the family of GNA-related lectins leads to changes in carbohydrate-binding specificity, as shown on N-glycan arrays.
Fouquaert
Elke
E
Laboratory of Biochemistry and Glycobiology, Department of Molecular Biotechnology, Ghent University, Coupure Links 653, B-9000 Ghent, Belgium.
Smith
David F
DF
Peumans
Willy J
WJ
Proost
Paul
P
Balzarini
Jan
J
Savvides
Savvas N
SN
Damme
Els J M Van
EJ
D000371:Agglutination; D000595:Amino Acid Sequence; D000998:Antiviral Agents / Q000737:chemistry / Q000494:pharmacology; D002240:Carbohydrate Sequence; D002241:Carbohydrates / Q000737:chemistry*; D002460:Cell Line; D027801:Galanthus / Q000737:chemistry*; D006801:Humans; D037241:Mannose-Binding Lectins / Q000096:biosynthesis / Q000737:chemistry*; D046228:Microarray Analysis; D008969:Molecular Sequence Data; D010843:Pichia / Q000378:metabolism; D037121:Plant Lectins / Q000096:biosynthesis / Q000737:chemistry*; D011994:Recombinant Proteins; D003313:Zea mays / Q000737:chemistry*
D000998:Antiviral Agents; D002241:Carbohydrates; D037241:Mannose-Binding Lectins; D037121:Plant Lectins; D011994:Recombinant Proteins; C063117:snowdrop lectin