Fast-scan cyclic voltammetry with thiol-modified mercury electrodes distinguishes native from denatured BSA

Electrochemistry in sensing of molecular interactions of proteins and their behavior in an electric field

Electrochemical methods can be used not only for the sensitive analysis of proteins but also for deeper research into their structure, transport functions (transfer of electrons and protons), and sensing their interactions with soft and solid surfaces. Last but not least, electrochemical tools are useful for investigating the effect of an electric field on protein structure, the direct application of electrochemical methods for controlling protein function, or the micromanipulation of supramolecular protein structures. There are many experimental arrangements (modalities), from the classic configuration that works with an electrochemical cell to miniaturized electrochemical sensors and microchip platforms. The support of computational chemistry methods which appropriately complement the interpretation framework of experimental results is also important. This text describes recent directions in electrochemical methods for the determination of proteins and briefly summarizes available methodologies for the selective labeling of proteins using redox-active probes. Attention is also paid to the theoretical aspects of electron transport and the effect of an external electric field on the structure of selected proteins. Instead of providing a comprehensive overview, we aim to highlight areas of interest that have not been summarized recently, but, at the same time, represent current trends in the field.

AGR2-AGR3 hetero-oligomeric complexes: Identification and characterization

In this paper we compare electrochemical behavior of two homolog proteins, namely anterior gradient 2 (AGR2) and anterior gradient 3 (AGR3), playing an important role in cancer cell biology. The slight variation in their protein structures has an impact on protein adsorption and orientation at charged surface and also enables AGR2 and AGR3 to form heterocomplexes. We confirm interaction between AGR2 and AGR3 (i) in vitro by immunochemical and constant current chronopotentiometric stripping (CPS) analysis and (ii) in vivo by bioluminescence resonance energy transfer (BRET) assay. Mutation of AGR2 in dimerization domain (E60A) prevents development of wild type AGR2 dimers and also negatively affects interaction with wild type AGR3 as shown by CPS analysis. Beside new information about AGR2 and AGR3 protein including their joint interaction, our work introduces possible applications of CPS in bioanalysis of protein complexes, including those relatively unstable, but important in the cancer research.

Bovine Serum Albumin Catalysed Hydrogen and Deuterium Evolution at Mercury Electrodes

The hydrogen evolution reaction (HER), catalysed by proteins at mercury electrodes and reflected in chronopotentiometric stripping peak H, provides a label-free and reagentless analytical technique that is sensitive to protein structure. Here we show how the kinetic isotope effect affected the HER catalysed by the protein bovine serum albumin (BSA). We found that the deuteron bond, which is stronger than that of a proton, contributed to less effective transport of deuterons mediated by BSA at the Hg|D₂ O interface, and enhanced structural stability of the surface-attached native BSA in D₂ O solution. A structural transition was also observed in the surface-attached urea-denatured BSA, and is probably due to the destabilisation of some secondary structural remnants retained by the 17 SS-bonds. Because the catalytically active groups involved in proton or deuteron transfer in native proteins are often exposed towards solutions and their protons exchange almost instantly, no signs of H/D exchange were observed in native BSA using peak H under the given conditions.

TinyFSCV: FSCV for the Masses

The ability to monitor neurochemical dynamics in target brain regions with a high degree of temporal resolution has assisted researchers in investigating the pathogenesis, and pathophysiology of a variety of neurological and psychiatric disorders. Current systems for neurochemical monitoring are bulky or expensive, limiting widespread exploration of this research field and preventing large-scale parallel experimentation. In this paper, we present a new miniaturized research platform, the TinyFSCV system, which can be used to monitor dynamic changes in neurochemicals through Fast-Scan Cyclic Voltammetry (FSCV). This system contains a precision voltage output circuit that can accurately output potentials between -0.55 to 2 V and scan a connected electrochemical cell at up to 400 V/s, the required speed to sense most neurochemicals with FSCV. In addition, the device includes precision current measurement circuity with a measurement range of -115 to [Formula: see text] capable of taking measurements at up to 56 KS/s. Four experiments are conducted to demonstrate the capability of the system. These consisted of: static bench tests, static ferrocene tests, and static and dynamic dopamine tests. These experiments demonstrate the ability of the miniaturized platform to accurately sense and measure neurochemicals. Ultimately, the TinyFSCV system is a platform that can enable large-scale, low-cost parallel experimentation to take place in the field of neurochemical monitoring. In addition, this device will increase the accessibility of neurochemical sensing, providing advanced tools and techniques to more researchers, and facilitating widespread exploration of the field of neurodynamics.