Identification of a chitinase from Apocheima cinerarius nucleopolyhedrovirus

Baculoviruses are important biological control agents against insect pests. In this work, a chitinase from Apocheima cinerarius nucleopolyhedrovirus (ApciNPV) as a fusion protein was highly over-expressed in Escherichia coli M 15 strain and affinity purified on Ni Sepharose 6 Fast Flow column. The modeling structure of ApciNPV chitinase indicated the protein contains a polycystic kidney 1(PKD1) domain on N-terminal and a characteristic catalytic domain formed α/β triosephosphate isomerase (TIM) barrel fold like other family 18 glycohydrolases. The ApciNPV chitinase displayed both endo- and exo-chitinase activities using fluorescent oligosaccharides. Moreover, assessed by LC50 (50% lethal concentration) values, the ApciNPV chitinase showed insecticidal activity against Apocheima cinerarius, Spodoptera exigua, Hyphantria cunea, Helicoverpa armigera and Lymantria dispar. The results suggest that ApciNPV chitinase may offer a potential application as a new tool to control pest. Key words: Apocheima cinerarius nucleopolyhedrovirus, chitinase, recombinant protein, insecticidal activity.