A pH‐Induced Reversible Conformational Switch Able to Control the Photocurrent Efficiency in a Peptide Supramolecular System

Abstract

External stimuli are potent tools that Nature uses to control protein function and activity. For instance, during viral entry and exit, pH variations are known to trigger large protein conformational changes. In Nature, also the electron transfer (ET) properties of ET proteins are influenced by pH‐induced conformational changes. In this work, a pH‐controlled, reversible 310‐helix to α‐helix conversion (from acidic to highly basic pH values and vice versa) of a peptide supramolecular system built on a gold surface is described. The effect of pH on the ability of the peptide SAM to generate a photocurrent was investigated, with particular focus on the effect of the pH‐induced conformational change on photocurrent efficiency. The films were characterized by electrochemical and spectroscopic techniques, and were found to be very stable over time, also in contact with a solution. They were also able to generate current under illumination, with an efficiency that is the highest recorded so far with biomolecular systems.

Synthesis and Characterization of a Supramolecular DNA-Inspired Nanowire

“…The presence of four Lys residues makes the peptide pH-sensitive [2,4]. We previously reported that Lys-containing trichogin analogs were able to switch their conformation reversibly between fully-developed α-helix and 310-helix in response to pH variation.…”

“…We also describe the effect on ET-through-peptide of a pH-controlled, reversible 310to α-helix conversion, with a focus on the effect of the pH-induced conformational change on photocurrent efficiency [2]. The biomolecular devices were characterized by electrochemical and spectroscopic techniques, and were able to generate current under illumination, with an efficiency that is the highest recorded so far with biomolecular systems.…”

“…Here, we report the synthesis of the peptide Thymine-[K 2,5,6,9 ]tric-Adenine (T-tric-A, Figure 1) and the characterization of its self-assembly in several environments. The primary structure of the peptide is: Thymine-CH2-CO-Aib-Lys-Leu-Aib-Lys-Lys-Leu-Aib-Lys-Ile-Leu-NH-(CH2)2-NH-CO-CH2-Adenine.…”

A Peptide-Based Trap for Metal Ions Studied by Electron Paramagnetic Resonance

“…Peptides are often able to provide a selective response to external stimuli, such as the presence of a specific analyte [9][10][11][12][13][14][15][16][17]. One of the most common reactions of peptides to an external stimulus is to undergo a conformational change that might be reversible [18][19][20]. The activation can be triggered by a non-covalent interaction between the analyte and the peptide binding site or induced by temperature or pressure variation or light [21][22][23][24][25].…”

Nickel Single-Atom Catalyst-Mediated Efficient Redox Cycle Enables Self-Checking Photoelectrochemical Biosensing with Dual Photocurrent Readouts

“…Usually, the photocurrent polarity switching strategy can be realized by tuning incident light wavelengths, − applied voltage, , pH of the electrolyte, − surface modification on semiconductors, ,, and so on. Among them, adjusting the applied voltage is a simple, portable way to reverse photocurrent polarity without extra cumbersome operating procedures.…”