Isolation and characterization of a fish F-type lectin from gilt head bream (Sparus aurata) serum

Abstract A novel fucose-binding lectin, designated SauFBP32, was purified by affinity chromatography on fucose–agarose, from the serum of the gilt head bream Sparus aurata . Electrophoretic mobility of the subunit revealed apparent molecular weights of 35 and 30 kDa under reducing and non-reducing conditions, respectively. Size exclusion analysis suggests that the native lectin is a monomer under the selected experimental conditions. Agglutinating activity towards rabbit erythrocytes was not significantly modified by addition of calcium or EDTA; activity was optimal at 37 °C, retained partial activity by treatment at 70 °C, and was fully inactivated at 90 °C. On western blot analysis, SauFBP showed intense cross-reactivity with antibodies specific for a sea bass ( Dicentrarchus labrax ) fucose-binding lectin. In addition, the similarity of the N-terminal sequence and a partial coding domain to teleost F-type lectins suggests that SauFBP32 is a member of this emerging family of lectins.