Oxidation of Cysteins in the Lens: Impact on the Structure and Function of Galectin-1

CARLOS M. A. GUARDIA; JULIO J. CARAMELO; MADIA TRUJILLO; SANTIAGO DI LELLA; GABRIEL RABINOVICH; DARÍO A. ESTRIN

Maldonado

Simposio; Thiol metabolism and redox regulation of cellular functions; 2011

Galectins constitute a family of multi-functional lectin proteins extensively distributed in a variety of tissues and animal species. They are defined by their specificity for b-galactoside sugars and consensus sequence in the carbohydrate recognition domain (CRD). Galectins are involved in immunomodulation phenomenon, adhesion and cell growth, inflammation, among other functions still poorly described. Although all the galectins have a highly homologous CRD, small differences in their binding specificity have been observed which are functionally relevant. The structural basis for this fine tuning is unknown.             Recently it was proposed that the functionality of galectins is modified with the redox state of cysteine residues, and in fact, several crystal structures of galectin-1 (Gal-1) showing one of its six cysteine residues oxidized to sulfenic acid have been reported. Either way, the relationship between redox state of these cysteine residues and ligand affinity is not clear, nor the mechanisms that could lead to oxidation of the protein on the biological level.