REAL

Competition of zinc(II) with cadmium(II) or mercury(II) in binding to a 12-mer peptide

Jancsó, Attila and Gyurcsik, Béla and Mesterházy, Edit and Berkecz, Róbert (2013) Competition of zinc(II) with cadmium(II) or mercury(II) in binding to a 12-mer peptide. JOURNAL OF INORGANIC BIOCHEMISTRY, 126. pp. 96-103. ISSN 0162-0134

[img]
Preview
Text
JIB_2013_126_96_elfogadott.pdf - Accepted Version

Download (1MB) | Preview

Abstract

Speciation of the complexes of zinc(II) with a dodecapeptide (Ac-SCPGDQGSDCSI-NH2), inspired by the metal binding domain of MerR metalloregulatory proteins, have been studied by pH-potentiometric titrations, UV, SRCD (synchrotron radiation circular dichroism) and 1H NMR experiments. (MerR is a family of transcriptional regulators the archetype of which is the Hg2+-responsive transcriptional repressor-activator MerR protein.) The aim of the ligand-design was to retain the advantageous metal binding features of MerR proteins in a model peptide for the efficient capture of toxic metal ions. The peptide binds zinc(II) via two deprotonated Cys-thiol groups and one of the Asp-carboxylates in the ZnL parent complex, possessing a remarkably high stability (logK = 9.93). In spite of the relatively long peptide loop, bis-complexes are also formed with the metal ion under basic conditions. In a competition with cadmium(II) or mercury(II), zinc(II) cannot prevent the binding of toxic metal ions by the thiolate donor groups of the ligand. Around neutral pH one equivalent of mercury(II) was shown to fully replace zinc(II) from the ZnL species. Partial replacement of zinc(II) from the peptide by one equivalent of cadmium(II), relative to zinc(II) and the ligand, is also presumable, nevertheless, spectroscopic data may suggest the formation of mixed metal ion complexes, as well. Based on the obtained results the investigated dodecapeptide can be a promising candidate for capturing toxic metal ions in practical applications.

Item Type: Article
Subjects: Q Science / természettudomány > QD Chemistry / kémia > QD02 Physical chemistry / fizikai kémia
Q Science / természettudomány > QD Chemistry / kémia > QD03 Inorganic chemistry / szervetlen kémia
Depositing User: Dr Attila Jancsó
Date Deposited: 17 Sep 2014 10:13
Last Modified: 30 Sep 2015 23:15
URI: http://real.mtak.hu/id/eprint/15200

Actions (login required)

Edit Item Edit Item