Capturing protein denaturation using electrical impedance technique

Lincon, Abhijit; Das, Soumen; DasGupta, Sunando

doi:10.1016/j.molliq.2022.119301

Cited by 3 publications

(3 citation statements)

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“…It was important to keep the films of the same size and keep the distance between the electrodes constant each time, which also proved to be time-consuming and cumbersome. To maintain uniformity, fabricated aluminum electrodes over a glass slide were used similar to that of Lincon et al Film forming solutions were drop cast in between the gap of the electrode, dried overnight, and connected to the instrument to record EIS. A schematic of this experimental setup is shown in Figure f.…”

Section: Resultsmentioning

confidence: 99%

“…The ionic conductivity of the materials was checked by EIS. To perform EIS, fabricated coplanar aluminum electrodes deposited on a silica glass substrate were used following the procedure of Lincon et al The separation between the electrodes is 471 ± 7 μm with a width of 462 ± 2 μm and a thickness of 155 ± 20 nm. 5 μL of the film-forming solutions were drop cast at the location of the interelectrode gap and dried overnight in a desiccator before recording the impedance.…”

Section: Methodsmentioning

confidence: 99%

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Biodegradable Solid Polymer Electrolytes from the Discarded Cataractous Eye Protein Isolate

Chowdhury,

Lincon,

Bhowmik

et al. 2024

ACS Appl. Bio Mater.

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The protein extracted from the discarded eye lenses postcataract surgery, referred to as the cataractous eye protein isolate (CEPI), is employed as a polymer matrix for the construction of solid polymer electrolyte species (SPEs). SPEs are expected to be inexpensive, conductive, and mechanically stable in order to be economically and commercially viable. Environmentally, these materials should be biodegradable and nontoxic. Taking these factors into account, we investigated the possibility of using a discarded protein as a polymer matrix for SPEs. Natural compounds sorbitol and sinapic acid (SA) are used as the plasticizer and cross-linker, respectively, to tune the mechanical as well as electrochemical properties. The specific material formed is demonstrated to have high ionic conductivity ranging from ∼2 × 10 −2 to ∼8 × 10 −2 S cm −1 . Without the addition of any salt, the ionic conductivity of sorbitol-plasticized non-cross-linked CEPI is ∼7.5 × 10 −2 S cm −1 . Upon the addition of NaCl, the conductivity is enhanced to ∼8 × 10 −1 S cm −1 . This study shows the possibility of utilizing a discarded protein CEPI as an alternative polymer matrix with further potential for the construction of tunable, flexible, recyclable, biocompatible, and biodegradable SPEs for flexible green electronics and biological devices.

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Section: Resultsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Biodegradable Solid Polymer Electrolytes from the Discarded Cataractous Eye Protein Isolate

Chowdhury,

Lincon,

Bhowmik

et al. 2024

ACS Appl. Bio Mater.

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“…However, electrical impedance measurements indicate not only cell number, but also changes in the behavior of individual cells associated with altered resistance and capacitance of the cytoplasm or cellular membranes (21). In addition, experiments on purified proteins show that protein denaturation is accompanied by exposure of hydrophobic amino acids to solvent and alters their dielectric properties, leading to increased impedance (22). Our initial experimental data showed that Hsp90 inhibitors cause an increase in impedance, even though Hsp90 inhibition suppresses cell proliferation.…”

Section: Hsp90 Inhibition Induces Cytoplasmic Changes Increasing Impe...mentioning

confidence: 89%

HSF1 is a direct sensor of proteotoxic stress.

Muller,

Simoncik,

Tichy

et al. 2023

Preprint

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Stress responses play a pivotal role in normal physiology, a feature exploited by cancer cells to facilitate growth, counteract genomic instability, and resist therapeutic stress. Heat shock factor-1 (HSF1), a major stress-response transcription factor, exhibits a significant upregulation in activity in cancer. While HSF1's role in transcription is relatively well-known, the mechanisms governing its activation, particularly in tumors, remain unclear. To determine whether HSF1 is the primary sensor of proteotoxic stress, we studied the range of conditions that modulate HSF1 activation both in vitro and in cells. We show that purified HSF1 adopts a stable monomeric conformation in vitro. Conditions that lead to protein denaturation, such as heat stress, molecular crowding, Hsp90 inhibition, and proteasome inhibition, directly trigger the activation of HSF1 by inducing conformational changes and trimer assembly. In contrast, proteosynthesis inhibition prevents HSF1 activation by reducing denatured proteins in the cell. Our findings highlight HSF1 as a direct sensor of proteotoxic stress, independent of post-translational modifications and molecular chaperones. Abrupt environmental changes causing protein denaturation induce a conformational change in monomeric HSF1, explaining the universal cellular response to proteotoxic stress. This activation mechanism underscores the cells' ability to initiate a protective response, enhancing chaperone activities to restore homeostasis.

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