Skip to main content
Article thumbnail
Location of Repository

The coordination of Ni2+ and Cu2+ ions to polyhistidyl motif of Hpn protein: is it as strong as we think it is?

By D. Witkowska, R. Politano, M. Rowinska-Zyrek, R. Guerrini, M. Remelli and H. Kozlowski


Hpn, one of Helicobacter pylori’s nickel accessory proteins, is an amazingly peculiar protein – almost half of its sequence consists of polyhistydyl residues. In this work, we try to understand the origin of this naturally occurring sequence, shedding some light upon the bioinorganic chemistry of Hpn’s numerous poly-His repeats. Using potentiometric, mass spectrometric and various spectroscopic techniques, we studied the Ni2+ and Cu2+complexes of the wild type Ac-THHHHYHGG-NH2 fragment of Hpn and of its six analogues, in which consecutive residues (His or Tyr) were replaced by Ala (Ala-substitution or Ala-scan approach), resulting in Ac-TAHHHYHGG-NH2, Ac-THAHHYHGG-NH2, Ac-THHAHYHGG-NH2, Ac-THHHAYHGG-NH2, Ac-THHHHAHGG-NH2 and Ac-THHHHYAGG-NH2 peptides, respectively. We found that the His-4 residue is critical for both Ni2+ and Cu2+ ion binding and the effectiveness of binding varies even if the substituted amino acid doesn’t take part in the direct binding

Topics: Helicobacter pylori, nickel homeostasis, histidine-rich proteins, complex-formation equilibria
Year: 2012
DOI identifier: 10.1002/chem.201200780
OAI identifier:
Download PDF:
Sorry, we are unable to provide the full text but you may find it at the following location(s):
  • (external link)
  • Suggested articles

    To submit an update or takedown request for this paper, please submit an Update/Correction/Removal Request.