title: The effect of the side chain length of Asp and Glu on coordination structure of Cu(2+) in a de novo designed protein.
abstract: Metal ions in proteins are important not only for the formation of the proper structures but also for various biological activities. For biological functions such as hydrolysis and oxidation, metal ions often adopt unusual coordination structures. We constructed a stable scaffold for metal binding to create distorted metal coordination structures. A stable four stranded alpha-helical coiled-coil structure was used as the scaffold, and the metal binding site was in the cavity created at the center of the structure. Two His residues and one Asp or Glu residue were used to coordinate the metal ions, AM2D and AM2E, respectively. Cu(2+) bound to AM2D with an equatorial planar coordination structure with two His, one Asp, and H(2)O as detected by electron spin resonance and UV spectral analyzes. On the other hand, Cu(2+) had a slightly distorted square planar structure when it bound two His and Glu in AM2E, due to the longer side-chain of the Glu residue as compared to the Asp residue. Computational analysis also supported the distorted coordination structure of Cu(2+) in AM2E. This construct should be useful to create various coordinations of metal ions for catalytic functions.
authors: Department of Material Sciences, Graduate School of Engineering, Nagoya Institute of Technology, Gokiso-chou, Nagoya 466-8555, Japan.
authors: Daigo
authors: D
authors: Shiga
authors: Daisuke
authors: D
authors: Nakane
authors: Tomohiko
authors: T
authors: Inomata
authors: Hideki
authors: H
authors: Masuda
authors: Masayuki
authors: M
authors: Oda
authors: Masanori
authors: M
authors: Noda
authors: Susumu
authors: S
authors: Uchiyama
authors: Kiichi
authors: K
authors: Fukui
authors: Yu
authors: Y
authors: Takano
authors: Haruki
authors: H
authors: Nakamura
authors: Toshihisa
authors: T
authors: Mizuno
authors: Toshiki
authors: T
authors: Tanaka
mesh_terms: D000595:Amino Acid Sequence; D001224:Aspartic Acid / Q000737:chemistry*; D001665:Binding Sites; D002614:Chelating Agents / Q000138:chemical synthesis / Q000737:chemistry*; D003300:Copper / Q000737:chemistry*; D004578:Electron Spin Resonance Spectroscopy; D018698:Glutamic Acid / Q000737:chemistry*; D008667:Metalloproteins / Q000737:chemistry*; D008958:Models, Molecular; D015202:Protein Engineering; D017433:Protein Structure, Secondary; D011993:Recombinant Fusion Proteins / Q000096:biosynthesis / Q000737:chemistry / Q000302:isolation & purification
chemical_list: D002614:Chelating Agents; D008667:Metalloproteins; D011993:Recombinant Fusion Proteins; D001224:Aspartic Acid; D018698:Glutamic Acid; D003300:Copper