The coordination of NiII and Cu(II) ions to the polyhistidyl motif of Hpn protein: is it as strong as we think?
Chemistry
; 18(35): 11088-99, 2012 Aug 27.
Article
in En
| MEDLINE
| ID: mdl-22829429
ABSTRACT
Hpn, one of Helicobacter pylori's nickel-accessory proteins, is an amazingly peculiar protein Almost half of its sequence consists of polyhistidyl (poly-His) residues. Herein, we try to understand the origin of this naturally occurring sequence, thereby shedding some light on the bioinorganic chemistry of Hpn's numerous poly-His repeats. By using potentiometric, mass spectrometric, and various spectroscopic techniques, we studied the Ni(II) - and Cu(II) complexes of the wild-type Ac-THHHHYHGG-NH(2) fragment of Hpn and of its six analogues, in which consecutive residues (His or Tyr) were replaced by Ala (Ala-substitution or Ala-scan approaches), thereby resulting in Ac-TAHHHYHGG-NH(2), Ac-THAHHYHGG-NH(2), Ac-THHAHYHGG-NH(2), Ac-THHHAYHGG-NH(2), Ac-THHHHAHGG-NH(2), and Ac-THHHHYAGG-NH(2) peptides. We found that the His4 residue is critical for both Ni(II) - and Cu(II) -ion binding and the effectiveness of binding varies even if the substituted amino acid does not take part in the direct binding interactions.
Full text:
1
Collection:
01-internacional
Database:
MEDLINE
Main subject:
Bacterial Proteins
/
Copper
/
Coordination Complexes
/
Histidine
/
Nickel
Language:
En
Journal:
Chemistry
Journal subject:
QUIMICA
Year:
2012
Type:
Article
Affiliation country:
Poland