3kso

Structure and Mechanism of the Heavy Metal Transporter CusA

spinqualitylabelsall models 3kso, resolution 4.37Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 3kso is a 1 chain structure with sequence from Escherichia coli. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Ligands: AG Related: 3kss Gene: cusA, ybdE, b0575, JW0564 (Escherichia coli) Resources: FirstGlance, OCA, RCSB, PDBsum Function [CUSA_ECOLI] Part of a cation efflux system that mediates resistance to copper and silver. 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 Gram-negative bacteria, such as Escherichia coli, frequently use tripartite efflux complexes in the resistance-nodulation-cell division (RND) family to expel various toxic compounds from the cell. The efflux system CusCBA is responsible for extruding biocidal Cu(I) and Ag(I) ions. No previous structural information was available for the heavy-metal efflux (HME) subfamily of the RND efflux pumps. Here we describe the crystal structures of the inner-membrane transporter CusA in the absence and presence of bound Cu(I) or Ag(I). These CusA structures provide new structural information about the HME subfamily of RND efflux pumps. The structures suggest that the metal-binding sites, formed by a three-methionine cluster, are located within the cleft region of the periplasmic domain. This cleft is closed in the apo-CusA form but open in the CusA-Cu(I) and CusA-Ag(I) structures, which directly suggests a plausible pathway for ion export. Binding of Cu(I) and Ag(I) triggers significant conformational changes in both the periplasmic and transmembrane domains. The crystal structure indicates that CusA has, in addition to the three-methionine metal-binding site, four methionine pairs-three located in the transmembrane region and one in the periplasmic domain. Genetic analysis and transport assays suggest that CusA is capable of actively picking up metal ions from the cytosol, using these methionine pairs or clusters to bind and export metal ions. These structures suggest a stepwise shuttle mechanism for transport between these sites. Crystal structures of the CusA efflux pump suggest methionine-mediated metal transport.,Long F, Su CC, Zimmermann MT, Boyken SE, Rajashankar KR, Jernigan RL, Yu EW Nature. 2010 Sep 23;467(7314):484-8. PMID:20865003 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

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