3dsp

Crystal structure of apo copper resistance protein CopK

spinqualitylabelsall models 3dsp, resolution 2.20Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 3dsp is a 1 chain structure with sequence from Cupriavidus metallidurans CH34. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Method: X-ray diffraction, Resolution 2.2Å Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Function COPK_CUPMC Involved in resistance to copper. Can bind up to 2 copper ions. Has higher affinity for Cu(+) than for Cu(2+). Evolutionary Conservation Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMed The bacterium Cupriavidus metallidurans CH34 is resistant to high environmental concentrations of many metal ions, including copper. This ability arises primarily from the presence of a large plasmid pMOL30 which includes a cluster of 19 cop genes that respond to copper. One of the protein products CopK is induced at high levels and is expressed to the periplasm as a small soluble protein (8.3 kDa). Apo-CopK associates in solution to form a dimer (K(D) approximately 10(-5) M) whose structure was defined by NMR and X-ray crystallography. The individual molecules feature two antiparallel beta-sheets arranged in a sandwich-like structure and interact through C-terminal beta-strands. It binds Cu(II) with low affinity (K(D)(Cu(II)) > 10(-6) M) but Cu(I) with high affinity (K(D)(Cu(I)) = 2 x 10(-11) M). Cu(I)-CopK was also a dimer in the solid state and featured a distorted tetrahedral site Cu(I)(S-Met)(3)(NCS). The isothiocyanato ligand originated from the crystallization solution. Binding of Cu(I) or Ag(I), but not of Cu(II), favored the monomeric form in solution. While Ag(I)-CopK was stable as isolated, Cu(I)-CopK was moderately air-sensitive due to a strong binding cooperativity between Cu(I) and Cu(II). This was documented by determination of the Cu(I) and Cu(II) binding affinities in the presence of the other ion: K(D)(Cu(I)) = 2 x 10(-13) M and K(D)(Cu(II)) = 3 x 10(-12) M, that is, binding of Cu(II) increased the affinity for Cu(I) by a factor of approximately 10(2) and binding of Cu(I) increased the affinity for Cu(II) by a factor of at least 10(6). Stable forms of both Cu(I)Cu(II)-CopK and Ag(I)Cu(II)-CopK were isolated readily. Consistent with this unprecedented copper binding chemistry, NMR spectroscopy detected three distinct forms: apo-CopK, Cu(I)-CopK and Cu(I)Cu(II)-CopK that do not exchange on the NMR time scale. This information provides a valuable guide to the role of CopK in copper resistance. Unprecedented Binding Cooperativity between Cu(I) and Cu(II) in the Copper Resistance Protein CopK from Cupriavidus metallidurans CH34: Implications from Structural Studies by NMR Spectroscopy and X-Ray Crystallography.,Chong LX, Ash MR, Maher MJ, Hinds MG, Xiao Z, Wedd AG J Am Chem Soc. 2009 Feb 24. PMID:19236095 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

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