Approaching the minimal metal ion binding peptide for structural and functional metalloenzyme mimicking

Publication: Research - peer-reviewJournal article – Annual report year: 2008

Without internal affiliation

  • Author: Jakab, Ida Noemi

    Unknown

  • Author: Lorincz, Orsolya

    University of Szeged, Department of Inorganic and Analytical Chemistry

  • Author: Jancso, Attila

    University of Szeged, Department of Inorganic and Analytical Chemistry

  • Author: Gajda, Tamas

    University of Szeged, Department of Inorganic and Analytical Chemistry

  • Author: Gyurcsik, Bela

    University of Szeged, Department of Inorganic and Analytical Chemistry

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The peptides Ac-His-Pro-His-Pro-His-NH(2)(L1) and Ac-Lys-His-Pro-His-Pro-His-Gln-NH(2) (L2) have been prepared and the equilibria of their proton, copper(II) and zinc(II) complexes in aqueous solution have been studied by the combination of pH-potentiometric titrations, UV/visible and circular dichroism (CD) spectroscopy. The latter methods also provided information on solution structure of the complexes formed under different conditions. Both ligands formed complexes with three imidazole nitrogens around the metal ion at pH similar to 7. In the L1 containing system precipitation of either copper(II) or zinc(II) complexes occurred upon slight increase of the pH. The re-titration of the filtered and acidified precipitates revealed that the insoluble materials were neutral complexes rather than metal-hydroxides. Indeed, by attaching amino acids with polar side-chains to the His-Pro-His-Pro-His template in L2 we could prevent any precipitation, and the soluble complexes around pH similar to 7 exerted three imidazole nitrogens and a (deprotonated) water molecule around the metal ions. To our knowledge L2 provides the first example of a short peptide preventing both the amide nitrogen coordination in copper(II) and the formation of copper(II) and zinc(II) hydroxides. The zinc(II) and copper(II) complexes at pH similar to 7 having similar structure to the natural hydrolytic and redox enzymes, respectively, showed considerable activity in hydrolytic cleavage assays with a model substrate (2-hydroxypropyl-4-nitrophenyl phosphate), as well as with native plasmid DNA, and in a superoxide dismutase-like reaction.
Keyword: MODEL,AMYLOID PRECURSOR PROTEIN,RESIDUES,NUCLEIC-ACIDS,COORDINATION,DNA,CLEAVAGE,ZINC(II) COMPLEXES,COPPER(II) COMPLEXES,HISTIDINE TRIAD SUPERFAMILY
Original languageEnglish
JournalDalton Transactions (Print Edition)
Publication date2008
Issue48
Pages6987-6995
ISSN1477-9226
DOIs
StatePublished
CitationsWeb of Science® Times Cited: 11
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