title: On the copper(II) ion coordination by prion protein HGGGW pentapeptide model.
abstract: The interaction of the octapeptide domain of the prion protein with the transition-metal-ion Cu2+ was studied at the DFT level by using the HGGGW pentapeptide as a model to mimic the PHGGGWGQ octarepeat sequence. Ten complexes, in which the metal ion exhibits different coordinations, were considered. Our results indicate that the lowest-energy structure is characterized by a tetracoordinated metal center and that this tendency of the ion to assume the square planar geometry is strong enough to prevent the addition of a further water molecule in its coordination sphere. The role of tryptophan was found to cause a lowering of the system energy due to the stabilizing effect of the electrostatic interaction between the Trp aromatic indole and histidine imidazole rings.
authors.affiliation: Dipartimento di Chimica and Centro di Calcolo ad Alte Prestazioni per Elaborazioni Parallele e Distribuite-Centro d'Eccellenza MIUR, Università della Calabria, I-87030 Arcavacata di Rende (CS), Italy.
authors.forename: T
authors.initials: T
authors.lastname: Marino
authors.forename: N
authors.initials: N
authors.lastname: Russo
authors.forename: M
authors.initials: M
authors.lastname: Toscano
mesh_terms: D002942:Circular Dichroism; D003300:Copper / Q000737:chemistry*; D018360:Crystallography, X-Ray; D006801:Humans; D009682:Magnetic Resonance Spectroscopy; D008956:Models, Chemical; D008958:Models, Molecular; D009842:Oligopeptides / Q000737:chemistry*; D010084:Oxidation-Reduction; D011328:Prions / Q000737:chemistry*; D021241:Spectrometry, Mass, Electrospray Ionization; D014364:Tryptophan / Q000737:chemistry
chemical_list: D009842:Oligopeptides; D011328:Prions; D003300:Copper; D014364:Tryptophan