Heterologous expression and molecular binding properties of AofleA, a fucose-specific lectin from nematophagous fungus Arthrobotrys oligospora.

Lectins are the primary recognition macromolecules for various types of fucosylation, a common eukaryotic post-translational modification. In this study, we report the heterologous expression and molecular binding properties of a fucose-specific lectin, AofleA, isolated from Arthrobotrys oligospora. This is the first reported fucose-specific lectin found in nematophagous fungi. The recombinant AofleA (r-AofleA) was expressed in Escherichia coli with high efficiency, yielding at least 500 mg of soluble and functional r-AofleA per liter of broth. Using hemagglutination inhibition assay and glycan microarray analysis, r-AofleA was found to be broadly specific for fucosylated glycans or oligosaccharides including Fucα(1-2), Fucα(1-3), Fucα(1-4) and Fucα(1-6) linkages, similar to Aleuria aurantia lectin (AAL). Frontal affinity chromatography showed that r-AofleA has high affinity towards PA-L-fucose with an average K value of 15 nM. These findings provide a basis for improved understanding of the structure and functions of AofleA during recognition and capture of prey nematodes by nematophagous fungus A. oligospora.