title: Critical amino acid residues for the specific binding of the Ti-recognizing recombinant ferritin with oxide surfaces of titanium and silicon.
abstract: The interactions of ferritins fused with a Ti-recognizing peptide (RKLPDA) and their mutants with titanium oxide substrates were explored with an atomic force microscope (AFM). The amino acid sequence of the peptide was systematically modified to elucidate the role of each amino acid residue in the specific interaction. Force measurements revealed a clear correlation among the sequences in the N-terminal domain of ferritin, surface potentials, and long-range electrostatic interactions. Measurements of adhesion forces clearly revealed that hydrogen bonds take part in the specific binding as well as the electrostatic interaction between charged residues and surface charges of Ti oxides. Moreover, our results indicated that not only the charged and polar residues but also a neutral residue (proline) govern the strength of the specific binding, with the order of the residues also being significant. These results demonstrate that the local structure of the peptide governs the special arrangement of charged residues and strongly affects the strength of the bindings.
authors.affiliation: Department of Electronic Chemistry, Interdisciplinary Graduate School of Science and Engineering, Tokyo Institute of Technology, 4259 Nagatsuta-cho, Midori-ku, Yokohama, Kanagawa 226-8502, Japan. hayashi@echem.titech.ac.jp
authors.forename: Tomohiro
authors.initials: T
authors.lastname: Hayashi
authors.forename: Ken-Ichi
authors.initials: K
authors.lastname: Sano
authors.forename: Kiyotaka
authors.initials: K
authors.lastname: Shiba
authors.forename: Kenji
authors.initials: K
authors.lastname: Iwahori
authors.forename: Ichiro
authors.initials: I
authors.lastname: Yamashita
authors.forename: Masahiko
authors.initials: M
authors.lastname: Hara
mesh_terms: D000268:Adhesiveness; D000596:Amino Acids / Q000235:genetics / Q000378:metabolism*; D000818:Animals; D005293:Ferritins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D006860:Hydrogen Bonding; D018625:Microscopy, Atomic Force; D008958:Models, Molecular; D050505:Mutant Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D009154:Mutation / Q000235:genetics; D010087:Oxides / Q000378:metabolism*; D011485:Protein Binding; D017434:Protein Structure, Tertiary; D011993:Recombinant Fusion Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D012825:Silicon / Q000378:metabolism*; D055672:Static Electricity; D013379:Substrate Specificity; D014025:Titanium / Q000737:chemistry / Q000378:metabolism*
chemical_list: D000596:Amino Acids; D050505:Mutant Proteins; D010087:Oxides; D011993:Recombinant Fusion Proteins; C009495:titanium dioxide; D005293:Ferritins; D014025:Titanium; D012825:Silicon