Galectin 3-β-galactobiose interactions.

Abstract Force spectroscopy has been used to investigate the interaction between the disaccharide β-galactobiose and the pro-metastatic regulatory protein galectin-3 (Gal3). The studies revealed specific interactions characterised by an off-rate dissociation constant k off  = 0.33 s −1 and interaction distance x  = 0.2 nm at zero applied force. These data suggest a lifetime for the interaction of 3.0 s. The results are consistent with the hypothesis that oral consumption of modified citrus pectin controls cancer metastasis by inhibiting the role of Gal3. The modification is considered to facilitate binding of pectin-derived galactan sidechains to Gal3 and inhibition of the roles of Gal3 as a pro-metastatic regulatory protein.