How the alpha-hydroxymethylserine residue stabilizes oligopeptide complexes with nickel(II) and copper(II) ions

Citation
P. Mlynarz et al., How the alpha-hydroxymethylserine residue stabilizes oligopeptide complexes with nickel(II) and copper(II) ions, J CHEM S DA, 7, 2000, pp. 1033-1038
Citations number
29
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Inorganic & Nuclear Chemistry
Journal title
JOURNAL OF THE CHEMICAL SOCIETY-DALTON TRANSACTIONS
ISSN journal
0300-9246 → ACNP
Volume
7
Year of publication
2000
Pages
1033 - 1038
Database
ISI
SICI code
0300-9246(2000)7:<1033:HTARSO>2.0.ZU;2-Z
Abstract
Potentiometric, spectroscopic and theoretical studies have shown that the a lpha-hydroxymethylserine (HmS) residue is a very specific amino acid residu e when inserted into a peptide sequence. The theoretical calculations as we ll as evaluated deprotonation microconstants indicated that in the HmS-HmS- His tripeptide the N-terminal ammonium group is more acidic than the imidaz ole nitrogen. The hydrogen bond formation between the N-terminal amino grou p and imidazole nitrogen stabilizes the cyclic conformation of the metal-fr ee peptide. The unusual gain in the 4N complex stability in the copper(II) and nickel(II) complexes with HmS-HmS-His ligands seems to derive from the enhancement of the pi-electron contribution to the metal-amide nitrogen bon d.