Molecular characterization of a novel peroxidase involved in Aedes aegypti chorion protein crosslinking.

Peroxidase-catalyzed chorion or eggshell protein crosslinking is an important biochemical event contributing to the formation of a protective chorion or eggshell in insects. Although the survival of the developing or developed embryo in the environment before hatching relies on the protection of the chorion, the identity of the peroxidative enzyme responsible for mediating chorion protein crosslinking has never been identified in any insect species. In this report, we describe the determination of partial peptide sequences of a novel mosquito chorion peroxidase through LC/MS/MS of a trypsin-digested chorion peroxidase active fraction, specific localization of the enzyme in the chorion through histochemical analysis, proteolytic processing of chorion peroxidase through comparison of the accurate mass of its intact mature enzyme with molecular mass of its deduced amino acid sequence, isolation of its cDNA based on chorion peroxidase partial amino acid sequences, evaluation of its transcriptional profile in developing ovaries, and application of the primary mosquito chorion peroxidase sequence in predicting potential chorion peroxidases in other species.