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New insights into the metal ion-peptide hydroxamate interactions: metal complexes of primary hydroxamic acid derivatives of common dipeptides in aqueous solution

Buglyó, Péter and Nagy, Eszter Márta and Farkas, Etelka and Sóvágó, Imre and Sanna, Daniele and Micera, Giovanni (2007) New insights into the metal ion-peptide hydroxamate interactions: metal complexes of primary hydroxamic acid derivatives of common dipeptides in aqueous solution. Polyhedron, Vol. 26 (8), p. 1625-1633. ISSN 0277-5387. Article.

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DOI: 10.1016/j.poly.2006.12.014

Abstract

Complex formation of primary dipeptide hydroxamic acids, L-Ala-L-AlaNHOH and L-Ala-L-SerNHOH, as well as the corresponding Z-protected ones, Z-L-Ala-L-AlaNHOH and Z-L-Ala-L-SerNHOH (Z = benzyloxycarbonyl), with iron(III), aluminium(III), nickel(II), copper(II) and zinc(II) was studied in aqueous solution by pH-potentiometric and spectroscopic (UV-Vis, EPR, CD, 1H NMR) methods. The exclusive formation of [O,O] chelated hydroxamate complexes was found with iron(III) and aluminium(III) with all the ligands. Formation of linkage isomers with the involvement of either [O,O] hydroxamate or [NHa2,CO] chelates was detected both in the zinc(II)-L-Ala-L-AlaNHOH and -L-Ala-L-SerNHOH systems. Upon increasing the pH, none of these chelating sets are capable of preventing the hydrolysis of the metal ion. The formation of stable complexes was found in the nickel(II) and copper(II) systems above pH ~ 6 with a [NH2, Namide, Nhydrox.] binding mode after deprotonation and coordination of the peptide amide and the hydroxamate group. With an excess of copper(II), the formation of trinuclear [Cu3HxL2]x+4 type (x = -4 to -6) complexes as the major species was also detected. Blocking the terminal amino group in the Z-protected ligands results in a dramatic decrease of the nickel(II) and zinc(II) binding strengths, and insoluble complexes with copper(II). No indication was found for the role of the hydroxyl group of the serine moiety in metal ion binding.

Item Type:Article
ID Code:1462
Status:Published
Refereed:Yes
Uncontrolled Keywords:Peptide hydroxamic acid, pH-potentiometry, metal complex, equilibrium, stability constant, micro constant
Subjects:Area 03 - Scienze chimiche > CHIM/03 Chimica generale e inorganica
Divisions:001 Università di Sassari > 01 Dipartimenti > Chimica
002 Altri enti e centri di ricerca del Nord Sardegna > CNR-Consiglio Nazionale delle Ricerche > Istituto di chimica biomolecolare, Sassari
Publisher:Pergamon / Elsevier
ISSN:0277-5387
Copyright Holders:© 2006 Elsevier
Additional Information:Pubblicato online il 16 dicembre 2006.
Deposited On:18 Aug 2009 10:05

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