Are Two Better Than One? A New Approach for Multidentate Grafting of Peptides to a Gold Substrate
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Abstract
Multidentate binding of two helical hexapeptides to a gold surface was obtained by introducing in the peptide chain a non ribosomial amino acid, i.e. the 4-amino-1,2-dithiolane-4-carboxylic acid (Adt) residue, a Cα-tetrasubstituted α-amino acid bearing a heterocyclic side chain characterized by a disulfide group. The two peptides, mainly formed by strongly helicogenic Cα-tetrasubstituted α-amino acids, were both functionalized at the N-terminus by a ferrocenoyl (Fc) group, but differ in the number of Adt residues included in the peptide chain: the former (Fc6Adt2) contains two Adt residues at positions 1 and 4, while its analog (Fc6Adt1) contains a single Adt at position 4, since the Adt at position 1 is substituted by an α-amino isobutyric acid (Aib) residue. This peptide design allowed us to explore the different electrochemical properties and morphologies shown by the two peptide layers immobilized on a gold surface by two (Fc6Adt2) or a single (Fc6Adt1) bidentate linker, respectively. The electrochemical activity of the ferrocenoyl probe embedded in the peptide film was characterized by cyclic voltammetry, chronoamperometry and square wave voltammetry, while the binding and the morphology of the peptide layers were studied by X-ray photoelectron spectroscopy (XPS) and ultra high vacuum scanning tunneling microscopy (UHV-STM), respectively. Significant differences were observed in the electron transfer (ET) properties of the two peptides investigated, which emerge from the diverging morphology achieved by the peptide layers on the gold surface. It was found that while a standing-up configuration of the peptide layer, realized by a single bidentate linkage, maximizes the ET efficiency, a lying down configuration (two Adt linkages) allows for precise positioning of Fc in the proximity of a gold surface.
Acknowledgement
This work was supported by the Italian Ministry of Education, University and Research (MIUR), PRIN 2010–2011 No. 2010FM738P, `Photophysical and photochemical properties of organic and biological compounds in solution and in organized systems'.
©2016 Walter de Gruyter Berlin/Boston
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Articles in the same Issue
- Frontmatter
- Editorial
- The First European Conference on Physical and Theoretical Chemistry
- Inverse Calibration Free fs-LIBS of Copper-Based Alloys
- Influence of the Ce:YAG Amount on Structure and Optical Properties of Ce:YAG-PMMA Composites for White LED
- Morphological Characterization of Shape-Controlled TiO2 Anatase through XRPD Analysis
- Optical and Geometric Properties of Free Silica Nanoparticles Studied by Small-Angle X-Ray Scattering
- Olive Mill Wastewater (OMW) Phenol Compounds Degradation by Means of a Visible Light Activated Titanium Dioxide-Based Photocatalyst
- The Electrochemical Degradation of Poly(3,4-ethylenedioxythiophene) Films Electrodeposited from Aqueous Solutions
- Repassivation Investigations on Aluminium: Physical Chemistry of the Passive State
- Excitation-Energy Transfer Paths from Tryptophans to Coordinated Copper Ions in Engineered Azurins: a Source of Observables for Monitoring Protein Structural Changes
- Are Two Better Than One? A New Approach for Multidentate Grafting of Peptides to a Gold Substrate
- Peptide Hydration Phenomena through a Combined Quantum Chemical and Bottom-Up Approach
- Relative Stability of the Scleroglucan Triple-Helix and Single Strand: an Insight from Computational and Experimental Techniques
- Revised Atomistic Models of the Crystal Structure of C–S–H with high C/S Ratio
- Assessing Accuracy of Exchange-Correlation Functionals for the Description of Atomic Excited States
- Photodegradation of Organic Pollutants on TiO2 P25 Surfaces Investigated by Transmission FTIR Spectroscopy Under In Situ UV-Vis Irradiation
