Fig. 3.

Comparison of experimental and calculated relative binding affinities. (Left, filled points) Results obtained with the QMPFF3 force field. (Right, open points) Results obtained with the MMFF force field. The solid line is the diagonal x = y, the horizontal bars show the statistical errors, the vertical bars show the experimental uncertainty derived from the data of refs. 36 and 37. Dashed lines show linear fits derived considering the calculated points as a function of the experimental ones (long dashes), and vice versa (short dashes). Agreement of the two fits for QMPFF3 demonstrates a high level of correlation in this case (see Table 4). Similarly, low correlation for MMFF is indicated by the substantial discrepancy in slope of the fits.