title: Two-metal ion, Ni(II) and Cu(II), binding alpha-helical coiled coil peptide.
abstract: Metalloproteins are an attractive target for de novo design. Usually, natural proteins incorporate two or more (hetero- or homo-) metal ions into their frameworks to perform their functions, but the design of multiple metal-binding sites is usually difficult to achieve. Here, we undertook the de novo engineering of heterometal-binding sites, Ni(II) and Cu(II), into a designed coiled coil structure based on an isoleucine zipper (IZ) peptide. Previously, we described two peptides, IZ-3adH and IZ-3aH. The former has two His residues and forms a triple-stranded coiled coil after binding Ni(II), Zn(II), or Cu(II). The latter has one His residue, which allowed binding with Cu(II) and Zn(II), but not with Ni(II). On the basis of these properties, we newly designed IZ(5)-2a3adH as a heterometal-binding peptide. This peptide can bind Cu(II) and Ni(II) simultaneously in the hydrophobic core of the triple-stranded coiled coil. The first metal ion binding induced the folding of the peptide into the triple-stranded coiled coil, thereby promoting the second metal ion binding. This is the first example of a peptide that can bind two different metal ions. This construction should provide valuable insights for the de novo design of metalloproteins.
authors.affiliation: Graduate School of Material Science, Nagoya Institute of Technology, Gokiso-cho, Nagoya 466-8555, Japan. ttanaka@nitech.ac.jp
authors.forename: Toshiki
authors.initials: T
authors.lastname: Tanaka
authors.forename: Toshihisa
authors.initials: T
authors.lastname: Mizuno
authors.forename: Souhei
authors.initials: S
authors.lastname: Fukui
authors.forename: Hidekazu
authors.initials: H
authors.lastname: Hiroaki
authors.forename: Jun-Ichi
authors.initials: J
authors.lastname: Oku
authors.forename: Kenji
authors.initials: K
authors.lastname: Kanaori
authors.forename: Kunihiko
authors.initials: K
authors.lastname: Tajima
authors.forename: Masahiro
authors.initials: M
authors.lastname: Shirakawa
mesh_terms: D000595:Amino Acid Sequence; D001665:Binding Sites; D002413:Cations, Divalent; D003300:Copper / Q000737:chemistry* / Q000378:metabolism; D004578:Electron Spin Resonance Spectroscopy; D008667:Metalloproteins / Q000138:chemical synthesis / Q000737:chemistry* / Q000378:metabolism; D008969:Molecular Sequence Data; D009532:Nickel / Q000737:chemistry* / Q000378:metabolism; D019906:Nuclear Magnetic Resonance, Biomolecular; D009842:Oligopeptides / Q000138:chemical synthesis / Q000737:chemistry / Q000378:metabolism; D017433:Protein Structure, Secondary
chemical_list: D002413:Cations, Divalent; D008667:Metalloproteins; D009842:Oligopeptides; D003300:Copper; D009532:Nickel