title: Speciation of copper-peptide complexes in water solution using DFTB and DFT approaches: case of the [Cu(HGGG)(Py)] complex.
abstract: The DFTB and DFT methods are applied to the study of different forms of the [Cu(HGGG)(Py)] complex in water, with the aim of identifying the most stable isomer. The DFTB calculations were possible thanks to a careful parametrization of the atom-atom repulsive energy terms for Cu-H, Cu-C, Cu-N, and Cu-O. The speciation process is carried out by computing different DFTB-steered molecular dynamics (SMD) trajectories, each of which ends in a well-defined different form. The last frame of each trajectory is subjected to geometry optimization at both DFTB and DFT levels, leading to a different isomer. From the corresponding energy values, a rank of relative stability of the isomers can be established. The computational protocol developed here is of general applicability to other metal-peptide systems and represents a new powerful tool for the study of speciation of metal-containing systems in water solution, particularly useful when the full characterization of the compound cannot be carried out on the basis of experimental results only.
authors.affiliation: Department of Biotechnologies and Biosciences, University of Milano-Bicocca, Piazza della Scienza 2, I-20126 Milano, Italy. maurizio.bruschi@unimib.it
authors.forename: Maurizio
authors.initials: M
authors.lastname: Bruschi
authors.forename: Luca
authors.initials: L
authors.lastname: Bertini
authors.forename: Vlasta
authors.initials: V
authors.lastname: Bonačić-Koutecký
authors.forename: Luca
authors.initials: L
authors.lastname: De Gioia
authors.forename: Roland
authors.initials: R
authors.lastname: Mitrić
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Zampella
authors.forename: Piercarlo
authors.initials: P
authors.lastname: Fantucci
mesh_terms: D003300:Copper / Q000737:chemistry*; D056004:Molecular Dynamics Simulation; D009942:Organometallic Compounds / Q000737:chemistry*; D010455:Peptides / Q000737:chemistry*; D011789:Quantum Theory; D012996:Solutions; D014867:Water / Q000737:chemistry
chemical_list: D009942:Organometallic Compounds; D010455:Peptides; D012996:Solutions; D014867:Water; D003300:Copper