Computational study of copper binding to DAHK peptide

We report DFT, semi-empirical and molecular mechanics calculations on the binding of Cu(II) to tetrapeptide DAHK, testing ability each predict coordination mode, conformation electronic spectra. • Testing computational models for predicting DAHK. LFMM generates accurate geometry but DFT required energy. Semi-empirical methods wrongly 3N2O coordination. Ligand Field Molecular Mechanics (LFMM), Density Functional Theory (DFT) Semi-Empirical are used study Asp-Ala-His-Lys (DAHK). Two conformational searching tools, LFMM/AMBER CREST/xTB, energy Cu-DAHK, using as a benchmark. In addition, DFT-predicted spectra evaluate modes found. reproduce experimentally determined coordination, distorted square planar arrangement 4 nitrogen ligands with axial fifth, oxygen ligand. However, CREST search was unsuccessful in mode changing bonding equatorial from N 3N1O.