Expression, Purification, and Applications of the Recombinant Lectin PVL from Psathyrella velutina Specific for Terminal N-Acetyl-Glucosamine.

The lectin PVL from the mushroom Psathyrella velutina is the founding member of novel family of fungal lectins. It adopts a seven bladed β-propeller presenting six binding sites specific for the recognition of non-reducing terminal N-acetyl-glucosamine (GlcNAc). The latest can be mainly found in glycoconjugates presenting truncated glycans where aberrant β-GlcNAc terminated glycans represent tumor markers. It can also be found in O-GlcNAcylated proteins where disruption of the O-GlcNAcylation homeostasis is associated with many physiopathological states. The recombinant PVL lectin proved to be a very powerful tool for labelling terminal GlcNAc antigens displayed by extracellular glycoconjugates but also by O-GlcNAcylated proteins found in the cytoplasm and nucleus. This chapter will describe how to produce and purify recombinant PVL and several applications for rPVL as probe for the detection of terminal O-GlcNAc.