INSTITUTO DE FISICA DE LIQUIDOS Y SISTEMAS BIOLOGICOS
Unidad Ejecutora - UE
congresos y reuniones científicas
Ligand Receptor Interaction: Aspirin-HSA as a testing case
H. ARIEL ALVAREZ; ANDRÉS N. MCCARTHY; J. RAÚL GRIGERA
Buzios - Brasil
Congreso; VII Iberoamerican Congress of Biophysics 2009; 2009
In this work we present a study of the interaction between Human Serum Albumin (HSA) and acetylsalicylic acid (ASA) by means of Molecular Dynamics simulations (MD).We start from a structure obtained from the Protein Data Bank, and use the AFM Pulling tool from GROMACS package, which simulates the action of the cantilever of an atomic force microscope on a molecule.After stabilization of the system, we quantify the force used to remove the ASA from its specific site of binding to HSA and calculate the mechanical non-equilibrium external work done during this process. The average work obtained using the finite sampling correction to the Jarzynski Equality gives a highest value for the variation of the Gibbs free energy (an equilibrium thermodynamical potential) associated to that process.To eliminate the effect of the solvent (treated explicitly, using the SPC/E model), we substract the so called `viscous work´, i.e. the work done to move the aspirin in the same trajectory through the solvent in absence of the protein.The results where compared with experimental data of the Albumin affinity constant for Aspirin obtained from quenching fluorescence method giving a good agreement.