Molecular characterization of a chitin-binding protein with the peritrophin-A domain from the Asiatic honeybee Apis cerana

•The cDNA of a chitin-binding protein with the peritrophin-A domain was cloned from Apis cerana (AcCBP).•AcCBP is a peritrophin protein that is expressed in the midgut and localized in the peritrophic membrane.•AcCBP functions as a chitin-binding protein.•AcCBP bound to fungal surfaces but did not show anti-fungal activity.

Chitin, a structural component of the insect peritrophic membrane (PM), is associated with chitin-binding proteins (CBPs). Insect CBPs have been studied extensively regarding their interactions with chitin in the structure and functions of the cuticle and PM. However, the functions of bee CBPs are poorly understood. In this study, we present the molecular cloning and functional characterization of a CBP from the Asiatic honeybee Apis cerana. A. cerana CBP (AcCBP) contains the peritrophin-A domain with a six-cysteine motif. AcCBP is exclusively expressed in the midgut and is localized in the PM of A. cerana worker bees. Recombinant AcCBP was expressed in baculovirus-infected insect cells, and it exhibited chitin-binding ability, thus indicating a role for AcCBP as a CBP in the PM of A. cerana worker bees. Furthermore, AcCBP bound to entomopathogenic fungal surfaces but did not show anti-fungal activity. Taken together, our data demonstrate that AcCBP functions as a CBP of the bee PM.

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