Structural and biological characterization of Nattectin, a new C-type lectin from the venomous fish Thalassophryne nattereri

► Fish lectins have been extensively described within tissues and cells associated with host defensive functions. ► Few reports describe the isolation of C-type lectins in venom of venomous fish. ► In this work we isolated and characterized a galactose-specific lectin, Nattectin in the venom of Brazilian venomous fish, that is known by the severity of the accidents provoked in fishermen and bathers. ► Nattectin is a basic, non-glycosilated, 15 kDa monomeric protein that exhibits hemagglutination activity that is independent of Ca2+. ► We also demonstrated a lectin activity for Nattectin in the innate immune system, especially in neutrophil mobilization in mice, indicating that marine organisms are source of immunomodulator agents.