Evaluation of dispersion-corrected density functional theory (B3LYP-DCP) for compounds of biochemical interest

An evaluation of a dispersion-corrected density functional theory method (B3LYP-DCP) [I.D. Mackie, G.A. DiLabio, Interactions in large, polyaromatic hydrocarbon dimers: application of density functional theory with dispersion corrections, J. Phys. Chem. A 112 (2008) 10968–10976] for three systems of biochemical interest is presented. Firstly, structures and energies of isomers of the tripeptide Phe-Gly-Phe have been compared with CCSD(T)/CBS//RI-MP2/cc-pVTZ literature values. In the system aromatic interactions compete with XH–π (X = C, N) interactions and hydrogen bonds which makes it a reliable model for proteins. The resulting mean absolute deviation between B3LYP-DCP and CCSD(T)/CBS relative energies is found to be 0.50 kcal mol−1. Secondly, a phenylalanine derivative featuring a CH–π interaction has been investigated. A comparison between the optimized geometry and X-ray crystal data shows that B3LYP-DCP accurately predicts the interaction between the two aromatic rings. Thirdly, the dipeptide Ac-Phe-Phe-NH2 which contains an edge-to-face interaction between two aromatic rings has been studied. The study demonstrates the general applicability of the B3LYP-DCP method on systems which features interactions typically present in biochemical compounds.

Figure optionsDownload high-quality image (93 K)Download as PowerPoint slideResearch highlights▶ Dispersion-corrected density functional theory. ▶ Dispersion-correction needed for accurate description of peptide model systems. ▶ General applicability of the dispersion-corrected B3LYP-DCP method.