Using cyclic voltammetry to probe the conformational transition of short elastin-like peptides

Elastin-like polypeptides (ELPs) are proteins naturally inspired by the hydrophobic domain of tropoelastin. ELPs are the repeating pentapeptide sequences of VPGXG (X can be any amino acid except proline) that undergo inverse transition behavior with temperature and salt stimuli. However, it remains challenging and unclear whether this transition, often accompanied by a conformational change, can be detected for short ELPs which are immobilized on surfaces. In this study, a sensing platform was developed based on the electrochemical activity of tyrosine to show conformational changes of newly designed, tethered, short ELPs with different hydrophobicity on gold working electrodes. Specifically, ELP sequences were modified with an N-terminal cysteine tag to attach to a solid gold surface via a thiol bond and modified with a C-terminal tyrosine tag, which can undergo electrochemical oxidation at the right potential. The ability of ELP conformational changes to modulate the oxidative current and indicate transition behavior was investigated via cyclic voltammetry. Additionally, the transition behavior of the short ELPs in solution was analyzed by UV-visible spectrometry for comparison. Overall, this study explores a distinct method for quantifying and studying the transition behavior of short, engineered peptides on a gold surface.