title: The binding mode of Ni-(L-His)2 in NikA revealed by X-ray crystallography.
abstract: The ABC-type importer NikABCDE mediates nickel acquisition in Escherichia coli. The periplasmic nickel-binding component NikA has a folding similar to that of the peptide transporter OppA and does not bind free nickel. Instead, we showed that the metal is tetra-coordinated by an organic tri-dentate molecule and His416. Conversely, it has been recently reported that NikA binds Ni-(L-His)2 and that addition of histidine increases the rate of nickel uptake in vivo. Here, we report the structure of NikA/Ni-(L-His)2 and show that histidine binding differs from peptide binding in OppA. The structure also confirms the central role of His416 in nickel binding.
authors: Institut de Biologie Structurale Jean-Pierre Ebel, Metalloproteins Group, UMR 5075, CEA, CNRS, Université Joseph Fourier-Grenoble 1, 41, rue Jules Horowitz 38027 Grenoble Cedex 1, France.
authors: Hugo
authors: H
authors: Lebrette
authors: Marina
authors: M
authors: Iannello
authors: Juan C
authors: JC
authors: Fontecilla-Camps
authors: Christine
authors: C
authors: Cavazza
mesh_terms: D018528:ATP-Binding Cassette Transporters / Q000737:chemistry* / Q000302:isolation & purification; D001665:Binding Sites; D002352:Carrier Proteins / Q000737:chemistry; D056831:Coordination Complexes / Q000737:chemistry*; D018360:Crystallography, X-Ray; D004926:Escherichia coli / Q000737:chemistry*; D029968:Escherichia coli Proteins / Q000737:chemistry* / Q000302:isolation & purification; D006639:Histidine / Q000737:chemistry*; D008074:Lipoproteins / Q000737:chemistry; D008956:Models, Chemical; D009532:Nickel / Q000737:chemistry*; D011485:Protein Binding; D017510:Protein Folding
chemical_list: D018528:ATP-Binding Cassette Transporters; D002352:Carrier Proteins; D056831:Coordination Complexes; D029968:Escherichia coli Proteins; D008074:Lipoproteins; C499290:OppA protein, E coli; C089849:nikA protein, E coli; D006639:Histidine; D009532:Nickel