2K0Q

Solution structure of CopK, a periplasmic protein involved in copper resistance in Cupriavidus metallidurans CH34

2K0Q の概要

• エントリーDOI: 10.2210/pdb2k0q/pdb
• NMR情報: BMRB: 15655
• 分子名称: Putative uncharacterized protein copK (1 entity in total)
• 機能のキーワード: copper, heavy metal resistance, open barrel, plasmid-encoded, metal binding protein
• 由来する生物種: CUPRIAVIDUS METALLIDURANS
• 細胞内の位置: Periplasm: Q58AD3
• タンパク質・核酸の鎖数: 1
• 化学式量合計: 8294.57

構造登録者

Bersch, B.,Favier, A.,Schanda, P.,Coves, J.,van Aelst, S.,Vallaeys, T.,Wattiez, R.,Mergeay, M. (登録日: 2008-02-12, 公開日: 2008-05-27, 最終更新日: 2024-05-29)

主引用文献

Bersch, B.,Favier, A.,Schanda, P.,van Aelst, S.,Vallaeys, T.,Coves, J.,Mergeay, M.,Wattiez, R.
Molecular structure and metal-binding properties of the periplasmic CopK protein expressed in Cupriavidus metallidurans CH34 during copper challenge.
J.Mol.Biol., 380:386-403, 2008

PubMed Abstract: The copK gene is localized on the pMOL30 plasmid of Cupriavidus metallidurans CH34 within the complex cop cluster of genes, for which 21 genes have been identified. The expression of the corresponding periplasmic CopK protein is strongly upregulated in the presence of copper, leading to a high periplasmic accumulation. The structure and metal-binding properties of CopK were investigated by NMR and mass spectrometry. The protein is dimeric in the apo state with a dissociation constant in the range of 10(-5) M estimated from analytical ultracentrifugation. Mass spectrometry revealed that CopK has two high-affinity Cu(I)-binding sites per monomer with different Cu(I) affinities. Binding of Cu(II) was observed but appeared to be non-specific. The solution structure of apo-CopK revealed an all-beta fold formed of two beta-sheets in perpendicular orientation with an unstructured C-terminal tail. The dimer interface is formed by the surface of the C-terminal beta-sheet. Binding of the first Cu(I)-ion induces a major structural modification involving dissociation of the dimeric apo-protein. Backbone chemical shifts determined for the 1Cu(I)-bound form confirm the conservation of the N-terminal beta-sheet, while the last strand of the C-terminal sheet appears in slow conformational exchange. We hypothesize that the partial disruption of the C-terminal beta-sheet is related to dimer dissociation. NH-exchange data acquired on the apo-protein are consistent with a lower thermodynamic stability of the C-terminal sheet. CopK contains seven methionine residues, five of which appear highly conserved. Chemical shift data suggest implication of two or three methionines (Met54, Met38, Met28) in the first Cu(I) site. Addition of a second Cu(I) ion further increases protein plasticity. Comparison of the structural and metal-binding properties of CopK with other periplasmic copper-binding proteins reveals two conserved features within these functionally related proteins: the all-beta fold and the methionine-rich Cu(I)-binding site.

PubMed: 18533181
DOI: 10.1016/j.jmb.2008.05.017

実験手法

SOLUTION NMR