Direct and Selective Immobilization of Proteins by Means of an Inorganic Material-Binding Peptide: Discussion on Functionalization in the Elongation to Material-Binding Peptide
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.
Conference Paper: Filter spectral selection for 3 wavelength optical pyrometry[Show abstract] [Hide abstract]
ABSTRACT: The filter spectral selection problem for a 3-wavelength optical pyrometer is analyzed in connection with the nonideal spectral distribution of infrared radiation from a high temperature body, taking into account spectral emissivity from a specific material. The level of spectral radiance is evaluated in order to maximize the ratio between the signals from three wavelengths, two at the time. A mathcad optimization procedure for filter spectral selection is proposedSemiconductor Conference, 2001. CAS 2001 Proceedings. International; 02/2001
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ABSTRACT: Cellulose, one of the most abundant carbon resources, is degraded by cellulolytic enzymes called cellulases. Cellulases are generally modular proteins with independent catalytic and cellulose-binding domain (CBD) modules and, in some bacteria, catalytic modules are noncovalently assembled on a scaffold protein with CBD to form a giant protein complex called a cellulosome, which efficiently degrades water-insoluble hard materials. In this study, a catalytic module and CBD are independently prepared by recombinant means, and are heterogeneously clustered on streptavidin and on inorganic nanoparticles for the construction of artificial cellulosomes. Heteroclustering of the catalytic module with CBD results in significant improvements in the enzyme's degradation activity for water-insoluble substrates. In particular, the increase of CBD valency in the cluster structure critically enhances the catalytic activity by improving the affinity for substrates, and clustering with multiple CBDs on CdSe nanoparticles generates a 7.2-fold increase in the production of reducing sugars relative to that of the native free enzyme. The multivalent design of substrate-binding domain on clustered cellulases is important for the construction of the artificial cellulosome, and the nanoparticles are an effective scaffold for increasing the valence of CBD in clustered cellulases. A new design is proposed for artificial cellulosomes with multiple CBDs on noncellulosome-derived scaffold structures.Small 02/2011; 7(5):656-64. · 7.82 Impact Factor
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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