Thermodynamic and kinetic aspects of metal binding to the histidine-rich protein, Hpn.
The histidine-rich protein, Hpn, binds to essential metals Ni2+, Cu2+, Zn2+ and a therapeutic metal Bi3+ with the in vitro affinities in the order of Cu2+ > Ni2+ > Bi3+ > Zn2+. In contrast, the in vivo (in E. coli) protection by the protein is in the order of Ni2+ > Bi3+ > Cu2+ approximately Zn2+. The release of Ni2+ from the protein follows a two-step process consisting of a rapidly established equilibrium and subsequently a rate-determining step (dissociation of Hpn-Ni...EDTA to Ni-EDTA). Our work suggests the nickel storage and homeostasis in H. pylori as the primary role of Hpn.
Ge
Ruiguang
R
Department of Chemistry, University of Hong Kong, Pokfulam, Hong Kong, PRC.
Zhang
Yi
Y
Sun
Xuesong
X
Watt
Rory M
RM
He
Qing-Yu
QY
Huang
Jian-Dong
JD
Wilcox
Dean E
DE
Sun
Hongzhe
H
D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000737:chemistry* / Q000235:genetics; D001667:Binding, Competitive; D001729:Bismuth / Q000737:chemistry / Q000494:pharmacology; D019327:Copper Sulfate / Q000737:chemistry / Q000494:pharmacology; D004492:Edetic Acid / Q000737:chemistry; D004926:Escherichia coli / Q000187:drug effects / Q000235:genetics / Q000254:growth & development; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D008670:Metals / Q000737:chemistry* / Q000494:pharmacology; D008969:Molecular Sequence Data; D009532:Nickel / Q000737:chemistry / Q000494:pharmacology; D011485:Protein Binding; D011506:Proteins / Q000737:chemistry* / Q000235:genetics; D011899:Ranitidine / Q000031:analogs & derivatives / Q000737:chemistry / Q000494:pharmacology; D013816:Thermodynamics; D019287:Zinc Sulfate / Q000737:chemistry / Q000494:pharmacology; D000099053:Histidine-Rich Glycoprotein
D001426:Bacterial Proteins; D008670:Metals; D011506:Proteins; D000099053:Histidine-Rich Glycoprotein; C029938:nickel sulfate; D019287:Zinc Sulfate; C073340:ranitidine bismuth citrate; D009532:Nickel; D011899:Ranitidine; D004492:Edetic Acid; D019327:Copper Sulfate; D001729:Bismuth