1IX2

Crystal Structure of Selenomethionine PcoC, a Copper Resistance Protein from Escherichia coli

1IX2 の概要

• エントリーDOI: 10.2210/pdb1ix2/pdb
• 関連するPDBエントリー: 1LYQ
• 分子名称: PcoC copper resistance protein (2 entities in total)
• 機能のキーワード: beta barrel, polymethionine cluster, metal binding protein
• 由来する生物種: Escherichia coli
• 細胞内の位置: Periplasm (By similarity): Q47454
• タンパク質・核酸の鎖数: 2
• 化学式量合計: 22596.34

構造登録者

Wernimont, A.K.,Huffman, D.L.,Finney, L.A.,Demeler, B.,O'Halloran, T.V.,Rosenzweig, A.C. (登録日: 2002-06-10, 公開日: 2002-11-27, 最終更新日: 2024-10-30)

主引用文献

Wernimont, A.K.,Huffman, D.L.,Finney, L.A.,Demeler, B.,O'Halloran, T.V.,Rosenzweig, A.C.
Crystal structure and dimerization equilibria of PcoC, a methionine-rich copper resistance protein from Escherichia coli
J.BIOL.INORG.CHEM., 8:185-194, 2003

PubMed Abstract: PcoC is a soluble periplasmic protein encoded by the plasmid-born pco copper resistance operon of Escherichia coli. Like PcoA, a multicopper oxidase encoded in the same locus and its chromosomal homolog CueO, PcoC contains unusual methionine rich sequences. Although essential for copper resistance, the functions of PcoC, PcoA, and their conserved methionine-rich sequences are not known. Similar methionine motifs observed in eukaryotic copper transporters have been proposed to bind copper, but there are no precedents for such metal binding sites in structurally characterized proteins. The high-resolution structures of apo PcoC, determined for both the native and selenomethionine-containing proteins, reveal a seven-stranded beta barrel with the methionines unexpectedly housed on a solvent-exposed loop. Several potential metal-binding sites can be discerned by comparing the structures to spectroscopic data reported for copper-loaded PcoC. In the native structure, the methionine loop interacts with the same loop on a second molecule in the asymmetric unit. In the selenomethionine structure, the methionine loops are more exposed, forming hydrophobic patches on the protein surface. These two arrangements suggest that the methionine motifs might function in protein-protein interactions between PcoC molecules or with other methionine-rich proteins such as PcoA. Analytical ultracentrifugation data indicate that a weak monomer-dimer equilibrium exists in solution for the apo protein. Dimerization is significantly enhanced upon binding Cu(I) with a measured delta(deltaG degrees )PubMed: 12459914
DOI: 10.1007/s00775-002-0404-9

実験手法

X-RAY DIFFRACTION (1.55 Å)