Recombinant synthesis of mouse Zn3-β and Zn4-α metallothionein 1 domains and characterization of their cadmium(II) binding capacity

M. Capdevila, N. Cols, N. Romero-Isart, R. Gonzàlez-Duarte, S. Atrian, P. Gonzàlez-Duarte

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79 Citations (Scopus)

Abstract

Genetic engineering, coupled with spectroscopic analyses, has enabled the metal binding proper ties of the α and β subunits of mouse metallothionein 1 (MT) to be characterized. A heterologous expression system in E.coli has led to high yields of their pure zinc-complexed forms. The cadmium(II) binding properties of recombinant Zn4-αMT and Zn3-βMT have been studied by electronic absorption and circular dichroism. The former binds Cd(II) identically to a fragments obtained from mammalian organs, showing that the recombinant polypeptide behaves like the native protein. Titration of Za3-βMT with CdCl2 results in the formation of Cd3-βMT. The addition of excess Cd(II) leads to Cd4-βMT which, with the extra loading of Cd(II), unravels to give rise isodichroically to Cd9-βMT. The effect of cadmium-displaced Zn(II) ions and excess Cd(II) above the full metal occupancy of three has been studied using Chelex-100. The Cd3-βMT species is stable in the presence of this strong metal-chelating agent.
Original languageEnglish
Pages (from-to)681-688
JournalCellular and Molecular Life Sciences
Volume53
Issue number8
DOIs
Publication statusPublished - 5 Nov 1997

Keywords

  • Cadmium binding
  • Chelex
  • Circular dichroism
  • E. coli expression
  • Metallothionein domains
  • Recombinant αMT
  • Recombinant βMT
  • UV-VIS difference spectra

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