As depicted in Table 2 , moderate correlation was exhibited by Surflex_Score and either the D_Score or the G_Score function; between D_Score and the ChemScore, LigScore1, LigScore2, PLP1, or PLP2 function; and between Jain and the LigScore1, LigScore2, or PLP2 function. This is consistent with virtually all of the scoring functions being designed to reflect the basic features in protein-ligand interactions including hydrogen bonds and hydrophobic contacts. Moreover, the binding scores computed by these scoring functions are all correlated, to some extent, to the known binding constants. Therefore, some intercorrelation between them is natural.