Lactose binding kinetics of the beta-galactosil binding protein Galectin-1

ROMERO, JUAN MANUEL; ESTRIN, DARIO; RABINOVICH, GABRIEL; DI LELLA, SANTIAGO

Villa Carlos Paz, Córdoba.

Congreso; XLII reunión anual de la Sociedad Argentina de Biofísica; 2013

Sociedad Argentina de Biofísica

Galectin-1 is a beta-Galatoside binding protein involved in cell comunication and diferentiation processes. It consists of a 134-aminoacid domain which has been proved to form a homodimer at physiological conditions. In a previous work, we have studied the thermodynamics of lactose binding and the simmetry of the homodimer applying computational simulation techniques . Now we employ guided molecular dynamics to characterise the binding and unbinding process, paying special attention to the molecular determinants of the kinetic barrier, which turns out to be mainly the result of hydrogen bonds breaking and forming. Furthermore, we measure the association and dissociation rate constants by stopped flow experiments. We find both constants to be 206M.s-1 and 0,98s-1 , respectively, and correlate them with the calculated energy barriers, while discussing results with previous reported kinetics experiments.