Toward Accurate Conformational Energies of Smaller Peptides and Medium-Sized Macrocycles: MPCONF196 Benchmark Energy Data Set

• DOI: 10.1021/acs.jctc.7b01074
• Publication Date: 2018-02-20T19:26:33Z
• Authors: Jan Řezáč; Daniel Bím; Ondrej Gutten; Lubomír Rulíšek
• Keywords: Benchmark (surveying); Data set

A carefully selected set of acyclic and cyclic model peptides several other macrocycles, comprising 13 compounds in total, has been used to calibrate the accuracy DFT(-D3) method for conformational energies, employing BP86, PBE0, PBE, B3LYP, BLYP, TPSS, TPSSh, M06-2X, B97-D, OLYP, revPBE, M06-L, SCAN, revTPSS, BH-LYP, ωB97X-D3 functionals. Both high- low-energy conformers, 15 or 16 each compound adding 196 denoted as MPCONF196 data set, were included, reference values obtained by composite protocol, yielding CCSD(T)/CBS extrapolated energies their DLPNO-CCSD(T)/CBS equivalents case larger systems. The latter was shown be near-quantitative (∼0.10–0.15 kcal·mol–1) agreement with canonical CCSD(T), provided TightPNO setting is used, and, therefore, can systems (likely up 150–200 atoms) problem studied here. At same time, it found that many D3-corrected DFT functionals provide results ∼1 kcal·mol–1 accuracy, which we consider quite encouraging. This result implies DFT-D3 methods be, example, safely efficient sampling algorithms. Specifically, DFT-D3/DZVP-DFT level calculation seems best trade-off between computational cost accuracy. Based on calculated data, have not any cheaper variant treatment since semiempirical (including DFTB) inferior (errors 3–5 kcal·mol–1).