Interaction of Cu2+ with His-Val-His and of Zn2+ with His-Val-Gly-Asp, two peptides surrounding metal ions in Cu,Zn-superoxide dismutase enzyme

A. Myari, G. Malandrinos, Y. Deligiannakis, J. C. Plakatouras, N. Hadjiliadis, Z. Nagy, I. Sòvágó

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58 Citations (Scopus)

Abstract

His-Val-His and His-Val-Gly-Asp are two naturally occuring peptide sequences, present at the active site of Cu,Zn-superoxide dismutase (Cu,Zn-SOD). The interactions of His-Val-His=A (copper binding site) with Cu(II) and of His-Val-Gly-Asp=B (zinc binding site) with Zn(II) have been studied by using both potentiometric and spectroscopic methods (visible, EPR, NMR). The stoichiometry, stability constants and solution structure of the complexes formed have been determined. The binding modes of the species [CuAH]2+ and [CuA]+ were characterized by histamine type of coordination. [CuA]+ is further stabilized by the formation of a macrochelate with the involvement of the imidazole of the C-terminal histidine. The existence of macrochelate results in a slight distortion of the coordination geometry providing good base for the development of enzyme models. The enhanced stability of the macrochelate suppresses the formation of bis-complexes as well as the amide deprotonation. This process, however, takes place at higher pH resulting in the formation of the 4 N- coordinated [NH2,N-,N-,N(im)] species [CuAH2-]-. On the other hand, in the case of the Zn(II)-His-Val-Gly-Asp system, coordination takes place at the terminal carboxylate in species [ZnBH2]2+. Monodentate binding occurs via the N-terminal imidazole in [ZnBH]+ while histamine type of coordination is possible in [ZnB], [ZnB2H]- and [ZnB2]2- species. Amide deprotonation does not take place in the case of Zn2+, hydroxo-complexes are formed instead.

Original languageEnglish
Pages (from-to)253-261
Number of pages9
JournalJournal of Inorganic Biochemistry
Volume85
Issue number4
DOIs
Publication statusPublished - Aug 15 2001

Keywords

  • Cu
  • Cu,Zn-superoxide dismutase enzyme
  • Enzyme superoxide dismutase
  • His-Val-Gly-Asp
  • His-Val-His

ASJC Scopus subject areas

  • Biochemistry
  • Inorganic Chemistry

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