Molecular Cloning and Characterization of a Subtilisin-Like Serine Protease Gene (Pr1) from the Medicinal Chinese Caterpillar Mushroom, Ophiocordyceps sinensis (Ascomycetes)

In the Chinese caterpillar mushroom Ophiocordyceps sinensis, a subtislin-like serine protease (Pr1) is one of the most important enzymes for its infection activity against insect cuticles. The Pr1 gene was isolated from the valuable Chinese medicinal fungus O. sinensis using rapid amplification of 5' and 3' complementary DNA ends. The 2079-bp full-length complementary DNA sequence containing the 1605-bp predicted open reading frame of the Pr1 gene was obtained (GenBank accession no. KF836756). The open reading frame encodes a protein comprising 534 amino acids. Protein sequence multiple alignment analysis revealed high homology with 16 other subtilisin serine proteases and exhibited the highly conserved catalytic domain (D195, H227, and S393). We also constructed a phylogenetic tree in this study. Further molecular studies are needed to elucidate the mechanisms of fungal infection.