The emerging question which this study is aimed to answer is: what impact do glutamines have on the stability of metal-peptide complexes? We focused our attention on the N-terminal domain of Hpn and Hpn-like proteins from Helicobacter pylori. Cu2+ and Ni2+ complexes of the model peptides MAHHENH2, MAHHEEQ-NH2, MAHHEQQ-NH2 and MAHHEQQHQA–NH2 were studied by means of 10 different thermodynamic and spectroscopic techniques, as well as through molecular modeling computation. Experimental results, in very good agreement with theoretical findings, lead to the not obvious conclusion that the stability of metal complexes distinctly increases with the number of glutamine residues present in the peptide, although glutamine side-chains do not directly take part in coordination. This peculiar finding allows one to look at polyglutamine sequences, not only the ones 15 present in some bacterial chaperons, but also those involved in several neurodegenerative diseases, from a new perspective.
Unexpected impact of the number of glutamine residues on metal complex stability
GUERRINI, Remo;REMELLI, Maurizio;
2013
Abstract
The emerging question which this study is aimed to answer is: what impact do glutamines have on the stability of metal-peptide complexes? We focused our attention on the N-terminal domain of Hpn and Hpn-like proteins from Helicobacter pylori. Cu2+ and Ni2+ complexes of the model peptides MAHHENH2, MAHHEEQ-NH2, MAHHEQQ-NH2 and MAHHEQQHQA–NH2 were studied by means of 10 different thermodynamic and spectroscopic techniques, as well as through molecular modeling computation. Experimental results, in very good agreement with theoretical findings, lead to the not obvious conclusion that the stability of metal complexes distinctly increases with the number of glutamine residues present in the peptide, although glutamine side-chains do not directly take part in coordination. This peculiar finding allows one to look at polyglutamine sequences, not only the ones 15 present in some bacterial chaperons, but also those involved in several neurodegenerative diseases, from a new perspective.I documenti in SFERA sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
