Analytical potentials from a b i n i t i o computations for the interaction between biomolecules. V. Formyl-triglycyl amide and water

Abstract

The interaction energy of formyl‐triglycyl amide (FTGA) with water has been analyzed following the techniques described in the previous papers of this series, where the interaction of water with the naturally occurring amino acids (and some of their zwitter ions) and with the four bases of DNA were examined. FTGA has been chosen in order to obtain a realistic atomic interaction potential of water with the backbone of proteins. Since the peptide linkage (CO–NH) and the terminal formyl group are formed by atoms that are in a different electronic environment than those previously analyzed in this series of papers, new ’’classes’’ of atoms have been added to our pairwise potential library. In the computation of the wavefunction and energy of the FTGA–water complex, we have considered two different conformations of FTGA and a total of 158 positions and orientations of the water molecule. As previously done, the computed SCF–LCAO–MO interaction energies have been fitted with a set of pair potentials of very simple analytical form. The water positions corresponding to energy minima are analyzed with the help of contour maps, where isoenergetic curves are displayed.