We present a DFT study of the structural and spectroscopic properties of the complex formed by Cu2+ with the peptide fragment Ac-PHREN-NH2, which encompasses the putative cell binding domain of angiogenin, as well as with its Ac-PHRQN-NH2 variant. Analysis of structures, energies and spectroscopic parameters has allowed to conclude that the metal coordination environment at pH 8 is formed by a nitrogen atom of His, two deprotonated amide groups, and an oxygen atom from the COO- side chain of Glu, in nice agreement with recent experimental results (La Mendola et al. in Dalton Trans, 39: 10678, 2010). Moreover, DFT results allowed to reveal that the Glu side chain of the Ac-PHREN-NH2 peptide is coordinated in equatorial position, in a tetrahedrically distorted square planar arrangement, fully disclosing the effects of Cu2+ binding on the structural properties of this key angiogenin portion. In the Ac-PHRQN-NH2 variant, the carboxylate group is replaced by a H2O molecule in a coordination arrangement similar to that of the wild-type system.
|Autori:||Bertini L; Bruschi M; Romaniello M; Zampella G; Tiberti M; Barbieri V; Greco C; La Mendola D; Bonomo RP; Fantucci P; De Gioia L|
|Titolo:||Copper coordination to the putative cell binding site of angiogenin: a DFT investigation|
|Anno del prodotto:||2012|
|Digital Object Identifier (DOI):||10.1007/s00214-012-1186-y|
|Appare nelle tipologie:||1.1 Articolo in rivista|