Adsorption kinetics of an engineered gold binding Peptide by surface plasmon resonance spectroscopy and a quartz crystal microbalance.
ABSTRACT The adsorption kinetics of an engineered gold binding peptide on gold surface was studied by using both quartz crystal microbalance (QCM) and surface plasmon resonance (SPR) spectroscopy systems. The gold binding peptide was originally selected as a 14-amino acid sequence by cell surface display and then engineered to have a 3-repeat form (3R-GBP1) with improved binding characteristics. Both sets of adsorption data for 3R-GBP1 were fit to Langmuir models to extract kinetics and thermodynamics parameters. In SPR, the adsorption onto the surface shows a biexponential behavior and this is explained as the effect of bimodal surface topology of the polycrystalline gold substrate on 3R-GBP1 binding. Depending on the concentration of the peptide, a preferential adsorption on the surface takes place with different energy levels. The kinetic parameters (e.g., K(eq) approximately 10(7) M(-1)) and the binding energy (approximately -8.0 kcal/mol) are comparable to synthetic-based self-assembled monolayers. The results demonstrate the potential utilization of genetically engineered inorganic surface-specific peptides as molecular substrates due to their binding specificity, stability, and functionality in an aqueous-based environment.
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ABSTRACT: Antibodies are affinity proteins with a wide spectrum of applications in analytical and therapeutic biology. Proteins showing specific recognition for a chosen molecular target can be isolated and their encoding sequence identified in vitro from a large and diverse library by phage display selection. In this work, we show that this standard biochemical technique rapidly yields a collection of antibody protein binders for an inorganic target of major technological importance: crystalline metallic gold surfaces. 21 distinct anti-gold antibody proteins emerged from a large random library of antibodies and were sequenced. The systematic statistical analysis of all the protein sequences reveals a strong occurrence of arginine in anti-gold antibodies, which corroborates recent molecular dynamics predictions on the crucial role of arginine in protein/gold interactions. Once tethered to small gold nanoparticles using histidine tag chemistry, the selected antibodies could drive the self-assembly of the colloids onto the surface of single crystalline gold platelets as a first step towards programmable protein-driven construction of complex plasmonic architectures. Electrodynamic simulations based on the Green Dyadic Method suggest that the antibody-driven assembly demonstrated here could be exploited to significantly modify the plasmonic modal properties of the gold platelets. Our work shows that molecular biology tools can be used to design the interaction between fully folded proteins and inorganic surfaces with potential applications in the bottom-up construction of plasmonic hybrid nanomaterials.05/2014;
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ABSTRACT: Phage display was used to find peptides specific for amorphous diamond-like carbon (DLC). A set of putative binders was analyzed in detail and one sequence was found that functioned both as a peptide fused to the pIII protein in M13 phage and as a peptide fused to the enzyme alkaline phosphatase (AP). The dissociation constant of the peptide-AP fusion on DLC was 63nM and the maximum binding capacity was 6.8pmol/cm(2). Multiple ways of analysis, including phage titer, enzyme-linked immunosorbent assay, and ellipsometry were used to analyze binding and to exclude possible false positive results. DLC binding peptides can be useful for self-assembling coatings for modifying DLC in specific ways.Colloids and surfaces B: Biointerfaces 04/2013; 110C:66-73. · 4.28 Impact Factor
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ABSTRACT: Inspired by biological material synthesis, synthetic biomineralization peptides have been screened through a laboratory evolution using bio-combinatorial techniques. In this study, using the fine examples in nature, silica binding peptides and gold binding peptides were fused together to form a hybrid peptide. We designed fusion peptides with different gold binding and silica binding parts. First we have tested the binding capability of the fusion peptides using quartz crystal microbalance on gold surface and silica surface. Secondly, S1G1 hybrid peptide enabled assembly of gold nanoparticles on silica surface was achieved. Finally, nanomaterial synthesis ability of the S1G1 peptide was presented by formation of a silica film on gold surface. In this study we are presenting a hybrid peptide tool for nano-hybrid assembly as a promising route for nanotechnology applications.Langmuir 02/2014; 30(8):2137. · 4.38 Impact Factor