Unfolded Molecules Research Articles

Alginate binding enhances the structural stability and potentiates the lytic activity of bacteriophage endolysin's partially folded conformation

Polysaccharide polymers are increasingly being used as chaperon-like macromolecules in assisting protein folding of unfolded protein molecules. They interact with unfolded or partially folded proteins in a charge and conformation specific manner that results in the formation of stable protein-polysaccharide complexes. In most of the cases, the complex formation of protein-polysaccharide is driven via non-covalent interactions that have found to endorse the activity of proteins. T4L (18.7 kDa) and T7L (17 kDa) endolysins belong to the hydrolase and amidase class of peptidoglycan degrading enzymes. Both T4L and T7L exist in partially folded forms and are devoid of lytic activity at low pH conditions. In the current study, we assessed the binding of alginate with T4L and T7L at pH 7 and 3 using variety of biophysical and biochemical techniques. Spectroscopic studies revealed differential structural modulations of partially folded T4L and T7L upon their interaction with alginate. Further, the complex formation of alginate with partially folded T4L/T7L was confirmed by ITC and STEM. Additionally, the formed complexes of alginate with both T4L/T7L PF endolysins were found to be chemically and enzymatically stable. Moreover, such complexes were also marked with differential enhancement in their lytic activities at acidic pH conditions. This implied the potency of alginate as an excellent choice of matrix to preserve the structural and functional integrity of partially folded forms of T4L and T7L at highly acidic conditions.

PH-regulated Tannic acid and soybean protein isolate adhesive for enhanced performance in plant-based meat analogues

A food adhesive comprising tannic acid (TA) and soybean protein isolate (SPI) was developed to establish a cohesive bond between soy protein gel and simulated fat. The impact of varying TA concentrations and pH levels on the adhesive’s rheology, thermal stability, chemical structure, and tensile strength were investigated. Rheological results revealed a gradual decrease in adhesive viscosity with increasing TA content. Differential scanning calorimetry (DSC) and thermal gravimetric (TG) results indicated that the stability of the adhesive improved with higher TA concentrations, reaching its peak at 0.50% TA addition. The incorporation of TA resulted in the cross-linking of amino group in unfolded SPI molecules, forming a mesh structure. However, under alkaline conditions (pH 9), adhesive viscosity and stability increased compared to the original pH. This shift was due to the disruption of the SPI colloidal charge structure, an increase in the stretching of functional groups, further unfolding of the structure, and an enhanced binding of SPI to TA. Under the initial pH conditions, SPI reacted with TA's active site to form covalent crosslinked networks and hydrogen bonds. In alkaline condition, beyond hydrogen and ionic bonding, the catechol structure was oxidized, forming an ortho-quinone that crosslinked SPI and created a denser structure. Tensile strength measurements and freeze–thaw experiments revealed that the adhesive exhibited maximum tensile strength and optimal adhesion with 0.75% TA at pH 9, providing the best overall performance. This study provides a new formulation and approach for developing plant-based meat analogues adhesives.

The miRNA‐mRNA Interactome of human trabecular meshwork cells treated with TGF‐ beta1

Aims/Purpose: Pseudoexfoliation glaucoma (XFG) is an aggressive form of secondary open angle glaucoma, associated with activation of the TGF‐β pathway by TGF‐β1. MicroRNAs are small non‐coding genes that regulate mRNA expression. To investigate the role of TGFβ1 in glaucomatous changes in the trabecular meshwork (TM) and to determine how mRNA expression may be regulated by microRNAs in this condition, we performed a bioinformatics analysis to determine the microRNA‐mRNA interactome.Methods: Primary human trabecular meshwork cells were obtained from normal donors (n = 4) and treated with TGF‐β1 at 5 ng/mL for 24 h. RNA was extracted and miRNA‐Seq and mRNA‐Seq performed. Differential mRNA and miRNA expression was determined using a bioinformatics pipeline consisting of FastQC, STAR, FeatureCounts, edgeR (miRNA) and DESeq2 (mRNA). Putative interactions between differentially expressed mRNAs and miRNAs, in which the direction of expression of the regulated mRNA was required to be opposite to that of the regulating miRNA, were determined using interaction databases miRTarBase, TarBase, TargetScan and miRWalk. To classify mRNA species by biological function and pathway, gene enrichment was performed using Enrichr.Results: The resulting microRNA‐mRNA interactome consisted of 1202 interactions. Some highly connected microRNAs were hsa‐let‐7e‐5p, hsa‐miR‐20a‐5p, hsa‐miR‐122‐5p, and hsa‐miR‐29c‐3p. Most genes in all enriched biological functions and pathways were indicated to be regulated by microRNAs. The sub‐interactomes of several specific XFG‐related enrichment terms such as oxidative stress, unfolded protein response, signal molecules and ECM remodelling were determined.Conclusions: This work presents a genome‐wide microRNA‐mRNA regulatory network for human TM cells treated with TGF‐β1 and may serve to generate unbiased hypotheses about regulatory functions of miRNAs found to be differentially expressed in XFG.

Structural, functional, and physicochemical characterization of fermented whey protein concentrates recovered from various fermented-distilled whey

The utilization of whey has become a challenge with the significant growth in the production of cheese and coagulated milk products. Consequently, we have developed cost-effective and waste-free production technologies for processing whey disposal into a variety of high-quality, value-added food products at the industrial level. This work constitutes a research on the impact of various alcoholic fermentations on functional, structural, and physicochemical properties of fermented whey proteins recovered from whey-based spirit production effluent. The results showed that surface hydrophobicity and sulfhydryl groups of fermented whey protein concentrates (FWPC) increased significantly in comparison with native whey protein concentrate, while the zeta-potential and particle size of non-supplemented FWPC and low-supplemented FWPC were not substantially affected by fermentation. Furthermore, the outcomes indicated that the non-and low-supplemented whey fermentation led to the improvement in the solubility of FWPCs dispersions, and enhancement in the emulsifying activity and stability of FWPCs. Size exclusion chromatography and SDS-Page results also demonstrated significantly increased β-Lg content in FWPCs, which might be attributed to the reinforcement of the β-Lg intramolecular and noncovalent bonds. The enhancement in functionality was probably due to the partially unfolded whey protein molecules, exposing more hydrophobic amino acid residues, thus making the protein more amphiphilic and capable. Nevertheless, high-yield alcoholic fermentation led to critical changes in the structural properties of whey proteins as evidenced by SEM results. Therefore, our findings suggested that the application of recovering FWPCs after producing premium quality potable whey-based spirit from the presence of non-and low-lactose supplemented whey is fully proposed as an industrially recommended alternative for food-grade protein production. • Fermentation process significantly increased general properties of FWPC. • More amphiphilic and capable proteins recovered due to exposed hydrophobic amino acids. • Increased β-Lg content in fermented whey protein leads to better functionality. • FWPC is proposed for manufacturing food-grade protein at the industrial level.

Effect of multi-mode sweep frequency ultrasound pretreatment on properties of the zeins and ACE inhibitory peptides activity of the hydrolysates

Effects of sweep frequency ultrasound (SFU) pretreatment of a new multifunctional ultrasonic equipment on hydrolysis characteristics of zeins and angiotensin-converting enzyme (ACE) inhibitory activity of zein hydrolysates were investigated. Degree of hydrolysis of zeins reached the highest of 25.93 % and 25.72 % at 40 kHz and 25/40 kHz, respectively. While 25/40 kHz increased solubility, surface hydrophobicity, particle size uniform of zeins and ACE inhibitory activities of the hydrolysates significantly. Endogenous fluorescence indicated that 25/40 kHz promoted unfolding of protein molecules and exposure of hydrophobic residues, thereby facilitating enzymatic hydrolysis. Circular dichroism spectrum and Fourier transform infrared spectrometer illustrated that 25/40 kHz unfolded protein molecules and decreased α-helical contents remarkably. Gel permeation chromatography showed that more small-molecule active peptides were obtained from hydrolysates at 25/40 kHz. In conclusion, SFU pretreatment at 25/40 kHz with the new equipment before proteolysis is an efficient method to improve ACE inhibitory activity of the hydrolysates.

Ultrasonic treatment of foam for the prevention of foam-induced pepsin inactivation

The phenomenon of foam-induced inactivation is a common challenge during foam fractionation of proteins. In this work, we attempted to use ultrasound to treat foam out of the foam fractionation column with the aim of minimizing the foam-induced protein inactivation using pepsin as a model protein. Firstly, the mechanisms by which ultrasound prevented the foam-induced pepsin inactivation during defoaming were explored. The results showed that ultrasound promoted the refolding of unfolded pepsin molecules at the gas-liquid interface to restore their activities during the desorption process from the interface and before dissolving into the foamate. Subsequently, the effects of ultrasonic power on the pepsin renaturation were analyzed, which revealed that the unfolding degree of pepsin in the foamate gradually decreased and then increased as the ultrasonic power increased. Correspondingly, the specific activity of pepsin in the foamate increased and then decreased. Finally, we explored the effects of defoaming efficiency, type of gas and pH. The results indicated that the decrease in defoaming efficiency and gas solubility in water facilitated the ultrasound-assisted pepsin renaturation in the pH range from 1.0 to 2.5. When air was applied in the foaming process, the specific activity of pepsin in the foamate with ultrasonic treatment was not significantly different from that in the feed solution at ultrasonic power of 400 W and pH 2.0. Collectively, these results indicate the ultrasonic treatment of foam effectively prevented the foam-induced pepsin inactivation.

Sequence grammar underlying the unfolding and phase separation of globular proteins

Aberrant phase separation of globular proteins is associated with many diseases. Here, we use a model protein system to understand how the unfolded states of globular proteins drive phase separation and the formation of unfolded protein deposits (UPODs). We find that for UPODs to form, the concentrations of unfolded molecules must be above a threshold value. Additionally, unfolded molecules must possess appropriate sequence grammars to drive phase separation. While UPODs recruit molecular chaperones, their compositional profiles are also influenced by synergistic physicochemical interactions governed by the sequence grammars of unfolded proteins and cellular proteins. Overall, the driving forces for phase separation and the compositional profiles of UPODs are governed by the sequence grammars of unfolded proteins. Our studies highlight the need for uncovering the sequence grammars of unfolded proteins that drive UPOD formation and cause gain-of-function interactions whereby proteins are aberrantly recruited into UPODs.

Pillar-structured 3D inlets fabricated by dose-modulated e-beam lithography and nanoimprinting for DNA analysis in passive, clogging-free, nanofluidic devices

We present the fabrication of three-dimensional inlets with gradually decreasing widths and depths and with nanopillars on the slope, all defined in just one lithography step. In addition, as an application, we show how these micro- and nanostructures can be used for micro- and nanofluidics and lab-on-a-chip devices to facilitate the flow and analyze single molecules of DNA. For the fabrication of 3D inlets in a single layer process, dose-modulated electron beam lithography was used, producing depths between 750 nm and 50 nm along a 30 μm long inlet, which is additionally structured with nanometer-scale pillars randomly distributed on top, as a result of incomplete exposure and underdevelopment of the resist. The fabrication conditions affect the slope of the inlet, the nanopillar density and coverage. The key parameters are the dose used for the electron beam exposure and the development conditions, like the developer’s dilution, stirring and development time. The 3D inlets with nanostructured pillars were integrated into fluidic devices, acting as a transition between micro and nanofluidic structures for pre-stretching and unfolding DNA molecules, avoiding the intrusion of folded molecules and clogging the analysis channel. After patterning these structures in silicon, they can be replicated in polymer by UV nanoimprinting. We show here how the inlets with pillars slow down the molecules before they enter the nanochannels, resulting in a 3-fold decrease in speed, which would translate to an improvement in the resolution for DNA optical mapping.

From Mesoscopic Functionalization of Silk Fibroin to Smart Fiber Devices for Textile Electronics and Photonics.

Bombyx mori silk fibers exhibit significant potential for applications in smart textiles, such as fiber sensors, fiber actuators, optical fibers, and energy harvester. Silk fibroin (SF) from B. mori silkworm fibers can be reconstructed/functionalized at the mesoscopic scale during refolding from the solution state into fibers. This facilitates the mesoscopic functionalization by engaging functional seeds in the refolding of unfolded SF molecules. In particular, SF solutions can be self‐assembled into regenerated fiber devices by artificial spinning technologies, such as wet spinning, dry spinning, microfluidic spinning, electrospinning, and direct writing. Meso‐functionalization manipulates the SF property from the mesoscopic scale, transforming the original silk fibers into smart fiber devices with smart functionalities, such as sensors, actuators, optical fibers, luminous fibers, and energy harvesters. In this review, the progress of mesoscopic structural construction from SF materials to fiber electronics/photonics is comprehensively summarized, along with the spinning technologies and fiber structure characterization methods. The applications, prospects, and challenges of smart silk fibers in textile devices for wearable personalized healthcare, self‐propelled exoskeletons, optical and luminous fibers, and sustainable energy harvesters are also discussed.

Particulate Matter Promotes Melanin Production through Endoplasmic Reticulum Stress‒Mediated IRE1α Signaling

Particulate matter (PM) is believed to be related to cardiovascular and respiratory diseases. The skin is also known to be affected by PM exposure as a result of skin barrier dysfunction, cutaneous inflammation, and apoptotic cell death. Epidemiological studies have suggested that PM is related to pigment spots. Recently, diesel exhaust particles are reported to cause a tanning response mediated by oxidative stress. However, the direct effects of PM on melanogenesis and the related mechanisms have not yet been clarified. Our study showed that PM can increase melanin production in melanocyte, mouse skin, and human skin models. RNA-sequencing analyses of melanocytes revealed that the expressions of unfolded protein response molecules were increased after PM exposure. In particular, IRE1α signaling pathway, which was consistently upregulated, was related to PM-triggered melanogenesis. In addition, PM-induced melanogenesis was abrogated by an IRE1α inhibitor. Therefore, our findings corroborate previous findings in melanocytes and in mouse and human models and also illuminate the involvement of the IRE1α pathway as a mechanism of PM-induced melanogenesis.

Rheological properties and interactions of fish gelatin-κ-carrageenan polyelectrolyte hydrogels: The effects of salt.

This study mainly explored the effects of low-concentration salts (0.1, 0.5 mM NaCl and Na2 SO4 ) on the gel, rheological and structural properties of fish gelatin (FG)-κ-carrageenan (κC) polyelectrolyte hydrogels. The results showed that κC could increase the gel strength, hardness, and chewiness of the FG-κC polyelectrolyte hydrogels, while the addition of salts had a negative effect. The rheological behaviors showed that the addition of salts reduced the apparent viscosity, gel, and melting points of the FG-κC polyelectrolyte hydrogels. Compared with NaCl, Na2 SO4 -treated FG-κC had lower gel strength, hardness, viscosity, gelation, and melting points, while the addition of salts increased the fluorescence intensity by unfolding FG molecules. The secondary structure analysis results showed that the addition of NaCl and Na2 SO4 decreased α-helix and β-sheet contents of FG-κC by destroying the hydrogen bond of FG-κC.

Von Willebrand Factor in Health and Disease

—Von Willebrand factor (vWF), the key component of hemostasis, is synthesized in endothelial cells and megakaryocytes and released into the blood as high molecular weight multimeric glycoproteins weighing up to 20 million Daltons. Blood plasma metalloprotease ADAMTS13 cleaves ultra-large vWF multimers to smaller multimeric and oligomeric molecules. The vWF molecules attach to the sites of damage at the surface of arterioles and capillaries and unfold under conditions of shear stress. On the unfolded vWF molecule, the regions interacting with receptors on the platelet membrane are exposed. After binding to the vWF filaments, platelets are activated; platelets circulating in the vessels are additionally attached to them, leading to thrombus formation, blocking of microvessels, and cessation of bleeding. This review describes the history of the discovery of vWF, presents data on the mechanisms of vWF secretion and its structure, and characterizes the processes of vWF metabolism in the body under normal and pathological conditions.

Effects of Protein Unfolding on Aggregation and Gelation in Lysozyme Solutions.

In this work, we investigate the role of folding/unfolding equilibrium in protein aggregation and formation of a gel network. Near the neutral pH and at a low buffer ionic strength, the formation of the gel network around unfolding conditions prevents investigations of protein aggregation. In this study, by deploying the fact that in lysozyme solutions the time of folding/unfolding is much shorter than the characteristic time of gelation, we have prevented gelation by rapidly heating the solution up to the unfolding temperature (~80 °C) for a short time (~30 min.) followed by fast cooling to the room temperature. Dynamic light scattering measurements show that if the gelation is prevented, nanosized irreversible aggregates (about 10–15 nm radius) form over a time scale of 10 days. These small aggregates persist and aggregate further into larger aggregates over several weeks. If gelation is not prevented, the nanosized aggregates become the building blocks for the gel network and define its mesh length scale. These results support our previously published conclusion on the nature of mesoscopic aggregates commonly observed in solutions of lysozyme, namely that aggregates do not form from lysozyme monomers in their native folded state. Only with the emergence of a small fraction of unfolded proteins molecules will the aggregates start to appear and grow.

Impact of DAA/water composition on PFSA ionomer conformation

Performance of a proton exchange membrane fuel cell (PEMFC) is significantly determined by the structure and composition of the electrode layer. Electrode layers are formed from inks consisting of platinum-doped carbon black particles, perfluorosulfonic acid (PFSA) ionomer and a dispersing solvent. Interaction between these materials mainly influences suspension stability, ionomer conformation and therewith layer morphology.We characterize the interplay between a short sidechain (SSC) PFSA ionomer (Aquivion® D79-25BS) and a solvent mixture (diacetone alcohol (DAA) and water with different weight ratios) by using Hansen solubility/dispersibility parameters (HSP) and by experimental tests. It was found that HSPs are well suitable to describe the ionomer/solvent interactions. In particular, the HSP difference in terms of the hydrogen bonds is responsible for the poor affinity between ionomer and solvent at low DAA concentrations. With increasing DAA content the affinity between ionomer and solvent increases as indicated by better matching HSPs. For an ionomer concentration of 4 wt%, Aquivion always forms molecular solutions for all DAA-in-water mixing ratios. Self-organization of the ionomer molecules changes from densely packed/collapsed molecules with highly deprotonated sulfonic acid side groups at low DAA concentrations to unfolded Aquivion molecules with a low dissociation degree of the sulfonic acid groups at high DAA concentrations.

Biophysical Properties and Cytotoxicity of Feruloylated Helix Lucorum Hemocyanin

For the first time Helix lucorum hemocyanin (HlH) has been feruloylated. Two HlH conjugates with 40- and 120- ferulic acid residues were prepared, denoted as FA-HlH-1 and FA-HlH-2. Expectedly, the feruloylation of HlH induced a rearrangement of the protein molecule, a decrease in the ?-helical structure at the expense of ß-structures was observed. Besides, the FA-HlH conjugates were more prone to aggregation, which is probably due to the stabilization of the partially unfolded protein molecules by non-covalent bonding. Interestingly, the thermal stability of HlH was not affected by the modification. The native and feruloylated HlH were not toxic to normal fibroblasts (BJ cells). We observed a decrease in cell viability of breast cancer MCF-7 cells to about 66% after a 48h exposure to 70 µg/well of FA-HlH-2.

Probing the Nongeneralized Amyloid Inhibitory Mechanism of Hydrophobic Chaperone.

Increasing prevalence of protein misfolding disorders urges the search for effective therapies. Although several antiaggregation molecules have been identified, their molecular process of aggregation and clinical trials are underway. The present study is focused on the mechanism through which phenyl butyrate (PB), a chemical chaperone, triggers inhibition of human serum albumin (HSA) fibrillation. Turbidity and Rayleigh light scattering (RLS) measurements reveal the marked presence of aggregates in HSA that were confirmed as amyloid fibrils by thioflavin T (ThT) and Congo red (CR) and were subsequently inhibited by PB in a dose dependent manner. ThT fluorescence kinetics reveals a decrease in the apparent rate constant, Kapp, in the presence of PB without triggering a lag phase in HSA suggesting PB's interference with the elongation phase. Dynamic light scattering (DLS) results display a reduction in the aggregate size in the presence of PB. Isothermal titration calorimetry (ITC) data reveals strong binding of PB at site II both at 25 °C (Kb ≈ 1.94 × 105 M-1) and 65 °C (Kb ≈ 2.90 × 104 M-1), mediated by hydrogen bonding. Overall, our finding establishes that PB stabilizes partially unfolded HSA molecules through hydrogen bonding, thereby preventing establishment of hydrogen bonds between them and hindering their progression into amyloid fibrils. This is in contrast to its chaperone effect manifested with other proteins.

Cryo-EM structure of a transthyretin-derived amyloid fibril from a patient with hereditary ATTR amyloidosis

ATTR amyloidosis is one of the worldwide most abundant forms of systemic amyloidosis. The disease is caused by the misfolding of transthyretin protein and the formation of amyloid deposits at different sites within the body. Here, we present a 2.97 Å cryo electron microscopy structure of a fibril purified from the tissue of a patient with hereditary Val30Met ATTR amyloidosis. The fibril consists of a single protofilament that is formed from an N-terminal and a C-terminal fragment of transthyretin. Our structure provides insights into the mechanism of misfolding and implies the formation of an early fibril state from unfolded transthyretin molecules, which upon proteolysis converts into mature ATTR amyloid fibrils.

Fabrication and characterization of acid-induced gels from thermally-aggregated egg white protein formed at alkaline condition

Cold gelation of egg white proteins (EWP) has still remained a challenge because they suffer from heat-induced gelation at low protein concentrations during the preheating step. This study suggested that adjusting pH of EWP solution at relatively high alkaline pH (i.e. 11.3) could inhibit the heat-induced gelation of EWP, allowing to produce thermally aggregated EWP (TA-EWP) at relatively high protein concentrations during the preheating step. Regarding SDS-PAGE, free –SH groups, circular dichroism, and surface hydrophobicity data, the preheating step at alkaline pH probably caused the TA-EWP are assembled from the partially unfolded protein molecules which stabilized by numerous disulfide bonds as well as hydrophobic interactions that develop a network of the β-sheet structures. The TA-EWPs are able to form acid-induced cold-set gels. SEM images showed the TA-EWP acid-induced gels had a honeycomb-like microstructure contained large serum pools. With increasing preheating temperature and protein content, the microstructure of the gels became more compact and all texture parameters including hardness, springiness, chewiness, cohesiveness as well as Young's modulus, true fracture stress (σ) and Hencky strain tend to increase. Furthermore, the water holding capacity (WHC) improved with increasing protein content and preheating temperature. All TA-EWP acid-induced gels exhibited a weak dependence of storage modulus (G′) with frequency and the G′ value of the acid-induced gels increased with increasing preheating temperature and protein content.

Effects of Different Denaturants on Properties and Performance of Soy Protein-Based Adhesive.

Chemical modification of soy protein, via crosslinking, is the preferred method for creating non-toxic, renewable, environmentally friendly wood adhesives. The denaturing process of protein is important for the adhesive performance improvement. In order to investigate the effect of different denaturing agents on the performance of soy protein-based adhesives before and after crosslinking modification. In this study, three different denaturing agents—urea (U), sodium dodecyl sulfate (SDS), and sodium hydrogen sulfite (SHS) and an epoxide crosslinking agent—Triglycidylamine (CA) were used to prepare soy protein-based adhesives. The results showed: (1) The denaturing agent unfolded protein molecules and exposed more hydrophobic groups to prevent water intrusion, which was mainly a contribution for the water resistance and performance improvement of soy protein-based adhesives. The wet shear strength was improved up to 91.3% (denaturing by urea). (2) After modifying by the crosslinking agent, the properties and performance improvement was due to the fact that the active groups on soybean protein molecules reacted with the crosslinking agent to form a crosslinking structure, and there is no obvious correlation with the hydrophobic groups of the protein. (3) The unfolded soybean protein molecules also expose hydrophilic groups, which facilitates the reaction between the crosslinking agent and protein to form a denser crosslinking structure to improve the performance of the adhesive. Particularly, after denaturing with SHS, the wet shear strength of the plywood bonded by the SPI-SHS-CA adhesive increased by 217.24%.

Abstract 1719: Copper levels and the p53 protein: A delicate balance

Abstract The tumor suppressor p53 is mutated in 50% of all cancers and in about 90% of small lung cancers. Mutations lead to loss of p53 expression or the expression of mutant p53 proteins. These mutants often lose WT function, but they have also been shown to acquire invasive and metastatic functions. p53 requires a zinc molecule in its core domain to fold properly and to function as a transcription factor and tumor suppressor. Loss of this zinc through competition with copper causes p53 to unfold and to lose its transcription function. Copper is an essential heavy metal required for a large variety of biological processes as it is required for the function of many enzymes. In cancer patients, increased serum levels of copper have been found and people with a predisposition for copper accumulation in the liver (Wilson’s disease, mutations in ATP7B) are prone to develop liver cancers. Our preliminary results have indicated that an unfolded WT p53 molecule does not only lose its transcription function, but also gains mutant p53-like functions in promoting invasion. Copper-induced unfolded p53 interacted with the mutant p53 specific interacting proteins Dicer, Ago, p63 and p73 and impaired p63 function. These results raise the question as to why a WT molecule would lose its function and whether it perhaps could act as a redox sensor. Experiments are ongoing to explore p53 mediated transcription in response to copper exposure. In addition, we are setting up mouse models to investigate p53 folding in vivo in response to mild increases in copper serum levels and we are developing methods to better determine p53 folding in patients and in mice. These results will help us assess p53 status in relation to serum metal levels in vivo and determine whether p53 is important in the development of cancers and metastasis. Citation Format: Patricia Muller, Yannick von Grabowiecki, Callum Hall. Copper levels and the p53 protein: A delicate balance [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 1719.