Direct and Selective Immobilization of Proteins by Means of an Inorganic Material-Binding Peptide: Discussion on Functionalization in the Elongation to Material-Binding Peptide

Institute of Multidisciplinary Research for Advanced Materials, Tohoku University, Katahira 2-1-1, Aoba-ku, Sendai 980-8577, Japan.
The Journal of Physical Chemistry B (Impact Factor: 3.61). 01/2010; 114(1):480-486. DOI: 10.1021/jp907731b
Source: PubMed

ABSTRACT Using an artificial peptide library, we have identified a peptide with affinity for ZnO materials that could be used to selectively accumulate ZnO particles on polypropylene-gold plates. In this study, we fused recombinant green fluorescent protein (GFP) with this ZnO-binding peptide (ZnOBP) and then selectively immobilized the fused protein on ZnO particles. We determined an appropriate condition for selective immobilization of recombinant GFP, and the ZnO-binding function of ZnOBP-fused GFP was examined by elongating the ZnOBP tag from a single amino acid to the intact sequence. The fusion of ZnOBP with GFP enabled specific adsorption of GFP on ZnO substrates in an appropriate solution, and thermodynamic studies showed a predominantly enthalpy-dependent electrostatic interaction between ZnOBP and the ZnO surface. The ZnOBP's binding affinity for the ZnO surface increased first in terms of material selectivity and then in terms of high affinity as the GFP-fused peptide was elongated from a single amino acid to intact ZnOBP. We concluded that the enthalpy-dependent interaction between ZnOBP and ZnO was influenced by the presence of not only charged amino acids but also their surrounding residues in the ZnOBP sequence.

1 Bookmark
  • [Show abstract] [Hide abstract]
    ABSTRACT: Elongated and flexuous recombinant nanoparticles were derived from Turnip mosaic virus to be used as bioscaffolds for increased peptide immunogenicity and peptide-specific antibody sensing. For this purpose, a 20-amino acid peptide derived from human vascular endotelial growth factor receptor 3 (VEGFR-3) was fused to the N-terminal region of Turnip mosaic virus coat protein (CP) by genetic insertion. The insertion was between codons corresponding to the first and second amino acids of the CP in two versions of a previously reported virus-derived vector. Systemic infections of two genetic constructs were achieved in two different plant hosts. The construct proved stable upon successive passages and generated virus nanoparticles identifiable under the electron microscope. The chimeric structures held the VEGFR-3 peptide. Purified VER3 nanoparticles were used to immunize mice, whose sera showed log increases of antibodies against the VEGFR-3 peptide when compared with mice immunized with peptide alone, thus providing the first quantitative data on the potential of elongated flexuous viruses for peptide immunogenicity increases. Purified VER3 nanoparticles also showed log increases in their ability to detect VER3 antibodies in sera, when used as reagents in ELISA assays, an application also used here for the first time.
    Journal of Biotechnology 09/2013; · 3.18 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: The growing usage of nanoparticles of zinc sulfide as quantum dots and biosensors calls for a theoretical assessment of interactions of ZnS with biomolecules. We employ the molecular-dynamics-based umbrella sampling method to determine potentials of mean force for 20 single amino acids near the ZnS (110) surface in aqueous solutions. We find that five amino acids do not bind at all and the binding energy of the remaining amino acids does not exceed 4.3 kJ/mol. Such energies are comparable to those found for ZnO (and to hydrogen bonds in proteins) but the nature of the specificity is different. Cysteine can bind with ZnS in a covalent way, e.g., by forming the disulfide bond with S in the solid. If this effect is included within a model incorporating the Morse potential, then the potential well becomes much deeper-the binding energy is close to 98 kJ/mol. We then consider tryptophan cage, a protein of 20 residues, and characterize its events of adsorption to ZnS. We demonstrate the relevance of interactions between the amino acids in the selection of optimal adsorbed conformations and recognize the key role of cysteine in generation of lasting adsorption. We show that ZnS is more hydrophobic than ZnO and that the density profile of water is quite different than that forming near ZnO-it has only a minor articulation into layers. Furthermore, the first layer of water is disordered and mobile.
    The Journal of Chemical Physics 03/2014; 140(9):095101. · 3.12 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: We determine potentials of the mean force for interactions of amino acids with four common surfaces of ZnO in aqueous solutions. The method involves all-atom molecular dynamics simulations combined with the umbrella sampling technique. The profiled nature of the density of water with the strongly adsorbed first layer affects the approach of amino acids to the surface and generates either repulsion or weak binding. The largest binding energy is found for tyrosine interacting with the surface in which the Zn ions are at the top. It is equal to 7 kJ mol(-1) which is comparable to that of the hydrogen bonds in a protein. This makes the adsorption of amino acids onto the ZnO surface much weaker than onto the well studied surface of gold. Under vacuum, binding energies are more than 40 times stronger (for one of the surfaces). The precise manner in which water molecules interact with a given surface influences the binding energies in a way that depends on the surface. Among the four considered surfaces the one with Zn at the top is recognized as binding almost all amino acids with an average binding energy of 2.60 kJ mol(-1). Another (O at the top) is non-binding for most amino acids. For binding situations the average energy is 0.66 kJ mol(-1). The remaining two surfaces bind nearly as many amino acids as they do not and the average binding energies are 1.46 and 1.22 kJ mol(-1). For all of the surfaces the binding energies vary between amino acids significantly: the dispersion in the range of 68-154% of the mean. A small protein is shown to adsorb onto ZnO only intermittently and with only a small deformation. Various adsorption events lead to different patterns in mobilities of amino acids within the protein.
    Physical Chemistry Chemical Physics 07/2013; · 4.20 Impact Factor