Raman study of in vivo synthesized Zn(II)-metallothionein complexes: Structural insight into metal clusters and protein folding

A Torreggiani, J Domènech, S Atrian, M Capdevila, A Tinti

Research output: Contribution to journalArticleResearchpeer-review

20 Citations (Scopus)

Abstract

Metallothioneins (MTs) are metal-chelating peptides that play an active role in zinc homeostasis. The participation of metal ligands other than cysteines and the presence of secondary structure elements in metal-MT complexes are fairly unknown, especially in nonvertebrate MTs. Here, four Zn(II) complexes of invertebrate MTs (mollusc, insect, nematode, and echinoderm) and the Zn(II)-MT complex of the mammalian MT1 isoform, heterologously synthesized in E. coli, were studied by analytic and spectroscopic techniques. By Raman and circular dichroism spectroscopy, new structural informations were obtained. The five analyzed MT isoforms consist largely of β-turns with the near exclusion of α-helical segments. Raman spectroscopy was revealed as an useful tool, providing information about the state of the cysteine sulfur atoms (metal coordinated and oxidized), the participation of histidine in metal coordination, and the molecular environment of tyrosine residues. In all the five Zn(II)-MT studied samples, acid-labile sulfide anions were found as nonproteic ligands, since sulfide-containing and sulfide-devoid species coexisted in the corresponding preparations. Significantly, Raman bands useful as markers of sulfide bridging ligands were identified. Overall, this work illustrates how the combination of analytical and spectroscopic techniques can be a very informative approach for the analysis of in vivo-synthesized metal-MT complexes, providing new data on the metal binding behavior of MTs from the most diverse organisms. © 2008 Wiley Periodicals, Inc.
Original languageEnglish
Pages (from-to)1114-1124
JournalBiopolymers
Volume89
Issue number12
DOIs
Publication statusPublished - 1 Dec 2008

Keywords

  • Circular dichroism
  • Histidine
  • Raman spectroscopy
  • Sulfide anions
  • Zn-metallothionein

Fingerprint

Dive into the research topics of 'Raman study of in vivo synthesized Zn(II)-metallothionein complexes: Structural insight into metal clusters and protein folding'. Together they form a unique fingerprint.

Cite this