On the copper(II) ion coordination by prion protein HGGGW pentapeptide model.
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.
Marino
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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.
Russo
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Toscano
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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
D009842:Oligopeptides; D011328:Prions; D003300:Copper; D014364:Tryptophan