cDNA cloning and structural characterization of a lectin from the mussel Crenomytilus grayanus with a unique amino acid sequence and antibacterial activity

•cDNA sequence encoding lectin from the mussel C. grayanus was determined.•The lectin is a member of a novel lectin family.•We show that the lectin is a β/α-protein.•The lectin adopts a ß-trefoilfold.•The lectin exhibits the bacterial-binding and growth suppressive activities.

An amino acid sequence of GalNAc/Gal-specific lectin from the mussel Crenomytilus grayanus (CGL) was determined by cDNA sequencing. CGL consists of 150 amino acid residues, contains three tandem repeats with high sequence similarities to each other (up to 73%) and does not belong to any known lectins family. According to circular dichroism results CGL is a β/α-protein with the predominance of β-structure. CGL was predicted to adopt a ß-trefoil fold. The lectin exhibits antibacterial activity and might be involved in the recognition and clearance of bacterial pathogens in the shellfish.