Rapid and accurate evaluation of the binding energies and the individual N-H•••O=C, N-H•••N, C-H•••O=C, and C-H•••N interaction energies for hydrogen-bonded peptide-base complexes

The binding energies of thirty-six hydrogen-bonded peptide-base complexes, including the peptide backbone-ase complexes and amino acid side chain-base complexes, are evaluated using the analytic potential energy function established in our lab recently and compared with those obtained from MP2, AMBER99, OPLSAA/L, and CHARMM27 calculations. The comparison indicates that the analytic potential energy function yields the binding energies for these complexes as reasonable as MP2 does, much better than the force fields do. The individual N-HaEuro broken vertical bar O=C, N-HaEuro broken vertical bar N, C-HaEuro broken vertical bar O=C, and C-HaEuro broken vertical bar N attractive interaction energies and C=OaEuro broken vertical bar O=C, N-HaEuro broken vertical bar H-N, C-HaEuro broken vertical bar H-N, and C-HaEuro broken vertical bar H-C repulsive interaction energies, which cannot be easily obtained from ab initio calculations, are calculated using the dipole-dipole interaction term of the analytic potential energy function. The individual N-HaEuro broken vertical bar O=C, C-HaEuro broken vertical bar O=C, C-HaEuro broken vertical bar N attractive interactions are about -5.3 +/- 1.8, -1.2 +/- 0.4, and -0.8 kcal/mol, respectively, the individual N-HaEuro broken vertical bar N could be as strong as aboutt -8.1 kcal/mol or as weak as -1.0 kcal/mol, while the individual C=OaEuro broken vertical bar O=C, N-HaEuro broken vertical bar H-N, C-HaEuro broken vertical bar H-N, and C-HaEuro broken vertical bar H-C repulsive interactions are about 1.8 +/- 1.1, 1.7 +/- 0.6, 0.6 +/- 0.3, and 0.35 +/- 0.15 kcal/mol. These data are helpful for the rational design of new strategies for molecular recognition or supramolecular assemblies.