Specific binding of silkworm Bombyx mori 30-kDa lipoproteins to carbohydrates containing glucose

Insect lectins are important as part of nonspecific self-defense, but their antifungal mechanisms remain to be elucidated. Fungi contain glucans on the cell surface and insect glucan-binding proteins are considered to be essential for antifungal mechanisms. We purified glucose-binding proteins from hemolymph of pupae of the silkworm Bombyx mori, and the amino acid sequence analysis showed that their two proteins are 30-kDa lipoproteins, major components of B. mori hemolymph. These lipoproteins specifically bound to glucose and glucans, suggesting that they are involved in insect self-defense systems.