2xl9

Structure and metal-loading of a soluble periplasm cupro-protein: Zn- CucA-closed (SeMet)

spinqualitylabelsall models 2xl9, resolution 2.06Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 2xl9 is a 2 chain structure with sequence from Aphanocapsa sp. (strain n-1). Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Ligands: TAM, ZN NonStd Res: MSE Related: 2xl7, 2xlg, 2xlf, 2xla Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT 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 A copper-trafficking pathway was found to enable Cu(2+) occupancy of a soluble periplasm protein, CucA, even when competing Zn(2+) is abundant in the periplasm. Here, we solved the structure of CucA (a new cupin) and found that binding of Cu(2+), but not Zn(2+), quenches the fluorescence of Trp(165), which is adjacent to the metal site. Using this fluorescence probe, we established that CucA becomes partly occupied by Zn(2+) following exposure to equimolar Zn(2+) and Cu(2+). Cu(2+)-CucA is more thermodynamically stable than Zn(2+)-CucA but k((Zn-->Cu)exchange) is slow, raising questions about how the periplasm contains solely the Cu(2+) form. We discovered that a copper-trafficking pathway involving two copper transporters (CtaA and PacS) and a metallochaperone (Atx1) is obligatory for Cu(2+)-CucA to accumulate in the periplasm. There was negligible CucA protein in the periplasm of DeltactaA cells, but the abundance of cucA transcripts was unaltered. Crucially, DeltactaA cells overaccumulate low M(r) copper complexes in the periplasm, and purified apoCucA can readily acquire Cu(2+) from DeltactaA periplasm extracts, but in vivo apoCucA fails to come into contact with these periplasmic copper pools. Instead, copper traffics via a cytoplasmic pathway that is coupled to CucA translocation to the periplasm. Structure and metal loading of a soluble periplasm cuproprotein.,Waldron KJ, Firbank SJ, Dainty SJ, Perez-Rama M, Tottey S, Robinson NJ J Biol Chem. 2010 Oct 15;285(42):32504-11. Epub 2010 Aug 10. PMID:20702411 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

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