Ab initio study of the second virial coefficient protein — protein on the basis of intermolecular potential energy surface

Document Type : Research Paper




Intermolecular potential energy surface (IPS) for protein — protein has been examined using RHF, DFT-B3LYP
and MP2 levels of theory with 6-31G, 6-31G* basis sets. A number of basis sets were used in order to evaluate
the basis set effects, at all three levels of theory, basis sets has significant effects on the calculated potential
energy curves (including position, depth and width of the potential well). Counterpoise (CP) correction has been
used to show the extent of the basis set superposition error (BSSE) on the potential energy curves obtained for
protein — protein system. The deepest BSSE-corrected potential well have been obtained at B3LYP level of
theory with 6-31G basis set. The second virial coefficients calculated this way are fitted to the initial coefficients
B2 varying E and ro, eventually some other parameters.