Structural insight into the distinct properties of copper transport by the Helicobacter pylori CopP protein.
Helicobacter pylori CopP (HpCopP) is a putative copper binding regulatory protein composed of 66 amino acid residues. The small HpCopP protein is homologous to CopZ, encoded by the E. hirae and B. subtilis cop operons. To clarify the role of HpCopP in copper metabolism in H. pylori, we studied the structural and copper binding characteristics by NMR spectroscopy. Based on the resonance assignments, the tertiary structure of HpCopP was determined. Unlike the betaalphabetabetaalphabeta fold of the homologous CopZ, HpCopP adopts the betaalphabetabetaalpha fold. The superposition with structures of other bacterial copper binding proteins showed that the global structure of HpCopP follows the general topology of the family, regardless of absence of the C-terminal beta-strand. The Cu(I) binding property of HpCopP was well conserved like CopZs: the structural changes due to Cu(I) and Ag(I) bindings were primarily restricted to the metal binding motif (CXXC motif). On the other hand, the Cu(II) binding property of CopP was different with that of CopZ: in the absence of reducing agent, Cu(II) ion oxidized a mutant HpCopP, resulting in disulfide bond formation in the CXXC motif. The Cu(II) ion binding property was evaluated using the mutant HpCopP, in which two amino acids were artificially introduced at the C-terminus, since the reduced state of the CXXC motif was more stabile in the mutant HpCopP without a reducing agent. Here, the structure and copper binding property of HpCopP are discussed in detail.
Park
Sung Jean
SJ
National Laboratory of Membrane Protein Structure, Research Institute of Pharmaceutical Sciences, College of Pharmacy, Seoul National University, San 56-1, Shillim-Dong, Kwanak-Gu, Seoul 151-742, Korea.
Jung
Yu-Sun
YS
Kim
Ji-Sun
JS
Seo
Min-Duk
MD
Lee
Bong Jin
BJ
D001426:Bacterial Proteins / Q000737:chemistry* / Q000235:genetics; D001665:Binding Sites; D002352:Carrier Proteins / Q000737:chemistry* / Q000235:genetics; D002413:Cations, Divalent / Q000378:metabolism; D002414:Cations, Monovalent / Q000378:metabolism; D003300:Copper / Q000378:metabolism; D004578:Electron Spin Resonance Spectroscopy; D016480:Helicobacter pylori / Q000737:chemistry*; D008958:Models, Molecular; D018832:Molecular Chaperones / Q000737:chemistry / Q000235:genetics; D019906:Nuclear Magnetic Resonance, Biomolecular; D010084:Oxidation-Reduction; D011487:Protein Conformation; D017433:Protein Structure, Secondary; D017434:Protein Structure, Tertiary
D001426:Bacterial Proteins; D002352:Carrier Proteins; D002413:Cations, Divalent; D002414:Cations, Monovalent; D018832:Molecular Chaperones; D003300:Copper