A new, 14-membered, tetraza cyclic tetrapeptide containing histidine and lysine side-chains, c(b3homo- LysdHisb-AlaHis), was designed, synthesized and characterized; its copper(II) binding properties were investigated in dependence of pH by potentiometric and spectroscopic methods. In line with previous studies of similar systems, the progressive involvement of amide nitrogens in copper(II) coordination was evidenced for pH values greater than 6. At physiological pH the dominant species consists of a cop- per(II) center coordinated by two amide nitrogens, an imidazole nitrogen and a water molecule. In con- trast, at pH values higher than 8.7, a copper(II) coordination environment consisting of four amide nitrogens in the equatorial plane and the axial imidazole ligands is formed as clearly indicated by spec- troscopic data and theoretical calculations. The behavior of this 14-membered cyclic tetrapeptide is com- pared to that of its 12-membered cyclic analog, particular attention being paid to the effects of ring size on the respective copper(II) binding abilities.
Impact of ring size on the copper(II) coordination abilities of cyclic tetrapeptides
PRATESI, ALESSANDRO;
2009-01-01
Abstract
A new, 14-membered, tetraza cyclic tetrapeptide containing histidine and lysine side-chains, c(b3homo- LysdHisb-AlaHis), was designed, synthesized and characterized; its copper(II) binding properties were investigated in dependence of pH by potentiometric and spectroscopic methods. In line with previous studies of similar systems, the progressive involvement of amide nitrogens in copper(II) coordination was evidenced for pH values greater than 6. At physiological pH the dominant species consists of a cop- per(II) center coordinated by two amide nitrogens, an imidazole nitrogen and a water molecule. In con- trast, at pH values higher than 8.7, a copper(II) coordination environment consisting of four amide nitrogens in the equatorial plane and the axial imidazole ligands is formed as clearly indicated by spec- troscopic data and theoretical calculations. The behavior of this 14-membered cyclic tetrapeptide is com- pared to that of its 12-membered cyclic analog, particular attention being paid to the effects of ring size on the respective copper(II) binding abilities.File | Dimensione | Formato | |
---|---|---|---|
Impact of ring size on the copper(II) coordination abilities of cyclic tetrapeptides.pdf
solo utenti autorizzati
Descrizione: Pdf editore - articolo principale
Tipologia:
Versione finale editoriale
Licenza:
NON PUBBLICO - Accesso privato/ristretto
Dimensione
355.39 kB
Formato
Adobe PDF
|
355.39 kB | Adobe PDF | Visualizza/Apri Richiedi una copia |
I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.