Galectin-1 from Ovine Placenta: Amino-acid Sequence, Physicochemical Properties and Implications in the T-cell Death

IIGLESIAS MM; RABINOVICH GA; AMBROSIO A; IVANOVIC V; SOTOMAYOR CE; C WOLFENSTEIN-TODEL

Blackwell Science Ltd.

Año: 1998 vol. 252 p. 400 - 400

n the present study we report the amino-acid sequence, carbohydrate specificity and overall biochemical and physicochemical properties of galectin-1, a beta-galactoside-binding lectin from ovine placenta. The complete amino-acid sequence, obtained by tryptic and chymotryptic digestion, revealed that this carbohydrate-binding protein shares all the absolutely preserved and critical residues found in other members of the mammalian galectin-1 subfamily. Moreover, conformational changes induced by protein interaction with its specific disaccharide were investigated by fourth-derivative spectral analysis, intrinsic tryptophan fluorescence measurements and circular dichroism. The first two methods indicated changes in the environment of aromatic residues, in agreement with the role of Trp in carbohydrate binding. The quenching of the fluorescence emission upon addition of lactose, allowed us to calculate the Kd for its interaction with the galectin, which was 0.157 +/- 0.02 mM. The far-ultr