Molecular and biochemical characterization of a Zeta-class glutathione S-transferase of the silkmoth

A cDNA encoding Zeta-class GST of the silkmoth, Bombyx mori (bmGSTZ), was cloned by a reverse transcriptase-polymerase chain reaction. The resulting clone was sequenced and deduced for amino acid sequence, which revealed 45–50% identities to Zeta-class GSTs from other organisms. A recombinant protein (rbmGSTZ) was functionally overexpressed in Bombyx mori cells in a soluble form and purified to homogeneity. rbmGSTZ was able to catalyze the biotranslation of glutathione with dichloroacetic acid. We found that the present GST-catalyzed dechlorination of permethrin and distributed abundantly in silkmoth strain exhibiting permethrin resistance. Our results suggest that bmGSTZ could contribute to permethrin resistance in lepidopteran.