title: Investigation on the individual contributions of N-H...O=C and C-H...O=C interactions to the binding energies of beta-sheet models.
abstract: In this article, the binding energies of 16 antiparallel and parallel beta-sheet models are estimated using the analytic potential energy function we proposed recently and the results are compared with those obtained from MP2, AMBER99, OPLSAA/L, and CHARMM27 calculations. The comparisons indicate that the analytic potential energy function can produce reasonable binding energies for beta-sheet models. Further comparisons suggest that the binding energy of the beta-sheet models might come mainly from dipole-dipole attractive and repulsive interactions and VDW interactions between the two strands. The dipole-dipole attractive and repulsive interactions are further obtained in this article. The total of N-H...H-N and C=O...O=C dipole-dipole repulsive interaction (the secondary electrostatic repulsive interaction) in the small ring of the antiparallel beta-sheet models is estimated to be about 6.0 kcal/mol. The individual N-H...O=C dipole-dipole attractive interaction is predicted to be -6.2 +/- 0.2 kcal/mol in the antiparallel beta-sheet models and -5.2 +/- 0.6 kcal/mol in the parallel beta-sheet models. The individual C(alpha)-H...O=C attractive interaction is -1.2 +/- 0.2 kcal/mol in the antiparallel beta-sheet models and -1.5 +/- 0.2 kcal/mol in the parallel beta-sheet models. These values are important in understanding the interactions at protein-protein interfaces and developing a more accurate force field for peptides and proteins.
authors.affiliation: School of Chemistry and Chemical Engineering, Liaoning Normal University, Dalian 116029, People's Republic of China. chwangcs@lnnu.edu.cn
authors.forename: Chang-Sheng
authors.initials: CS
authors.lastname: Wang
authors.forename: Chang-Liang
authors.initials: CL
authors.lastname: Sun
mesh_terms: D008958:Models, Molecular; D010455:Peptides / Q000737:chemistry; D017433:Protein Structure, Secondary; D011506:Proteins / Q000737:chemistry*; D013816:Thermodynamics
chemical_list: D010455:Peptides; D011506:Proteins