Hypoviruses are positive-strand RNA mycoviruses that attenuate virulence of their pathogenic fungal hosts [E1]. They employ a gene expression strategy that involves the autocatalytic processing of the N-terminal portion of encoded polyproteins by papain-like protease domains. The prototypic hypovirus CHV-1/EP713, responsible for virulence attenuation (hypovirulence) of the chestnut blight fungus Cryphonectria parasitica, encodes two contiguous open reading frames (ORFs) designated ORF A and ORF B, which contain N-terminal proteases p29 and p48, respectively. Protease p29 functions as a suppressor of the RNA silencing defense response, while p48 is required for viral RNA replication [1,2,3,4].

The HAV papain-like protease p29 is a cysteine protease, which forms the peptidase family C7 [E2]. A Cys and a His catalytic residue are essential for autocatalytic cleavage at a glycine dipeptide clevage site located at the C-terminus of the domain [1,2,4].

The HAV papain-like protease p48 is a cysteine protease, which forms the peptidase family C8 [E3]. A Cys and a His catalytic residue are essential for autocatalytic cleavage between the cleavage site residues Gly and Ala located at the C-terminus of the domain [1,2,4].

The profiles we developed cover the entire HAV papain-like proteases p48 and p29 domains.