Averaged total interaction energy between nucleotide substrates and RNases.

The total interaction energy (Etotal) was computed as a sum of van der Waals (Evdw) and electrostatics (Eel) energy, averaged over 2,000 snapshots (see Methods for details). Difference >5 kcal/mol in Etotal is considered significant for preference of substrate ACAC and AUAU binding to the same RNase; such cases are underlined. Note that the case of bRNaseA-ACAC at 300 K is close to this criterion (5.1 kcal/mol) but is not marked. The repulsive Evdw observed in case of hRNase7-AUAU at 310 K is marked in bold.