Hpn and Hpn-like are Helicobacter pylori cytoplasmic proteins involved in the homeostasis of nickel, required for the metal-enzymes urease and Ni-Fe hydrogenase, essential for the bacterium colonization in the human stomach. Hpn is an amazingly peculiar protein: almost half of its sequence consists of polyhistydyl repeats. On the other hand, Hpn-like proteins are rich in glutamine residues. Our research group was recently involved in a study on the Ni(II) and Cu(II) complexes of different fragments and analogues of Hpn and Hpn-like proteins, in order to shed light on the role of the consecutive His and Gln residues in metal-ion binding [1,2] (see Figure). The encouraging results pushed us to continue this investigation, focusing the attention on the N-terminal domain of Hpn-like proteins. Cu(II) and Ni(II) complexes of peptide models (MAHHE-NH2, MAHHEEQ-NH2, MAHHEQQ-NH2 and MAHHEQQHQA–NH2) were studied by means of different thermodynamic and spectroscopic techniques, as well as through molecular modeling computations.
Poly-His and poly-Gln sequences in bacterial proteins: tempting sites for metal ions to interact with
REMELLI, Maurizio;
2012
Abstract
Hpn and Hpn-like are Helicobacter pylori cytoplasmic proteins involved in the homeostasis of nickel, required for the metal-enzymes urease and Ni-Fe hydrogenase, essential for the bacterium colonization in the human stomach. Hpn is an amazingly peculiar protein: almost half of its sequence consists of polyhistydyl repeats. On the other hand, Hpn-like proteins are rich in glutamine residues. Our research group was recently involved in a study on the Ni(II) and Cu(II) complexes of different fragments and analogues of Hpn and Hpn-like proteins, in order to shed light on the role of the consecutive His and Gln residues in metal-ion binding [1,2] (see Figure). The encouraging results pushed us to continue this investigation, focusing the attention on the N-terminal domain of Hpn-like proteins. Cu(II) and Ni(II) complexes of peptide models (MAHHE-NH2, MAHHEEQ-NH2, MAHHEQQ-NH2 and MAHHEQQHQA–NH2) were studied by means of different thermodynamic and spectroscopic techniques, as well as through molecular modeling computations.I documenti in SFERA sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.