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Current Protein & Peptide Science 2020Heat shock proteins (HSPs) are molecular chaperones involved in a variety of life activities. HSPs function in the refolding of misfolded proteins, thereby contributing... (Review)
Review
Heat shock proteins (HSPs) are molecular chaperones involved in a variety of life activities. HSPs function in the refolding of misfolded proteins, thereby contributing to the maintenance of cellular homeostasis. Heat shock factor (HSF) is activated in response to environmental stresses and binds to heat shock elements (HSEs), promoting HSP translation and thus the production of high levels of HSPs to prevent damage to the organism. Here, we summarize the role of molecular chaperones as anti-heat stress molecules and their involvement in immune responses and the modulation of apoptosis. In addition, we review the potential application of HSPs to cancer therapy, general medicine, and the treatment of heart disease.
Topics: Animals; Antineoplastic Agents; Apoptosis; Benzoquinones; Gene Expression Regulation; Heat-Shock Proteins; Humans; Lactams, Macrocyclic; Male; Myocardial Reperfusion Injury; Oxidative Stress; Plants; Prostatic Neoplasms; Protein Refolding; Response Elements; Signal Transduction; Stress, Physiological
PubMed: 31713482
DOI: 10.2174/1389203720666191111113726 -
Biotechnology Advances Dec 2022Inclusion bodies (IBs) often emerge upon overexpression of recombinant proteins in E. coli. From IBs, refolding is necessary to generate the native protein that can be... (Review)
Review
Inclusion bodies (IBs) often emerge upon overexpression of recombinant proteins in E. coli. From IBs, refolding is necessary to generate the native protein that can be further purified to obtain pure and active biologicals. This work focusses on refolding as a significant process step during biopharmaceutical manufacturing with an industrial perspective. A theoretical and historical background on protein refolding gives the reader a starting point for further insights into industrial process development. Quality requirements on IBs as starting material for refolding are discussed and further economic and ecological aspects are considered with regards to buffer systems and refolding conditions. A process development roadmap shows the development of a refolding process starting from first exploratory screening rounds to scale-up and implementation in manufacturing plant. Different aspects, with a direct influence on yield, such as the selection of chemicals including pH, ionic strength, additives, etc., and other often neglected aspects, important during scale-up, such as mixing, and gas-fluid interaction, are highlighted with the use of a quality by design (QbD) approach. The benefits of simulation sciences (process simulation and computer fluid dynamics) and process analytical technology (PAT) for seamless process development are emphasized. The work concludes with an outlook on future applications of refolding and highlights open research inquiries.
Topics: Biological Products; Escherichia coli; Inclusion Bodies; Protein Refolding; Recombinant Proteins
PubMed: 36252795
DOI: 10.1016/j.biotechadv.2022.108050 -
Progress in Molecular Biology and... 2024Many diseases are caused by misfolded and denatured proteins, leading to neurodegenerative diseases. In recent decades researchers have developed a variety of compounds,... (Review)
Review
Many diseases are caused by misfolded and denatured proteins, leading to neurodegenerative diseases. In recent decades researchers have developed a variety of compounds, including polymeric inhibitors and natural compounds, antibodies, and chaperones, to inhibit protein aggregation, decrease the toxic effects of amyloid fibrils, and facilitate refolding proteins. The causes and mechanisms of amyloid formation are still unclear, and there are no effective treatments for Amyloid diseases. This section describes research and achievements in the field of inhibiting amyloid accumulation and also discusses the importance of various strategies in facilitating the removal of aggregates species (refolding) in the treatment of neurological diseases such as chemical methods like as, small molecules, metal chelators, polymeric inhibitors, and nanomaterials, as well as the use of biomolecules (peptide and, protein, nucleic acid, and saccharide) as amyloid inhibitors, are also highlighted.
Topics: Humans; Amyloid; Animals; Protein Aggregates
PubMed: 38811084
DOI: 10.1016/bs.pmbts.2024.03.012 -
Journal of Molecular Biology Oct 2021The use of force probes to induce unfolding and refolding of single molecules through the application of mechanical tension, known as single-molecule force spectroscopy... (Review)
Review
The use of force probes to induce unfolding and refolding of single molecules through the application of mechanical tension, known as single-molecule force spectroscopy (SMFS), has proven to be a powerful tool for studying the dynamics of protein folding. Here we provide an overview of what has been learned about protein folding using SMFS, from small, single-domain proteins to large, multi-domain proteins. We highlight the ability of SMFS to measure the energy landscapes underlying folding, to map complex pathways for native and non-native folding, to probe the mechanisms of chaperones that assist with native folding, to elucidate the effects of the ribosome on co-translational folding, and to monitor the folding of membrane proteins.
Topics: Animals; Humans; Models, Molecular; Protein Folding; Proteins; Single Molecule Imaging
PubMed: 34418422
DOI: 10.1016/j.jmb.2021.167207 -
Advances in Colloid and Interface... Oct 2022Although the anionic surfactant sodium dodecyl sulfate, SDS, has been used for more than half a century as a versatile and efficient protein denaturant for protein... (Review)
Review
Although the anionic surfactant sodium dodecyl sulfate, SDS, has been used for more than half a century as a versatile and efficient protein denaturant for protein separation and size estimation, there is still controversy about its mode of interaction with proteins. The term "rod-like" structures for the complexes that form between SDS and protein, originally introduced by Tanford, is not sufficiently descriptive and does not distinguish between the two current vying models, namely protein-decorated micelles a.k.a. the core-shell model (in which denatured protein covers the surface of micelles) versus beads-on-a-string model (where unfolded proteins are surrounded by surfactant micelles). Thanks to a combination of structural, kinetic and computational work particularly within the last 5-10 years, it is now possible to rule decisively in favor of the core-shell model. This is supported unambiguously by a combination of calorimetric and small-angle X-ray scattering (SAXS) techniques and confirmed by increasingly sophisticated molecular dynamics simulations. Depending on the SDS:protein ratio and the protein molecular mass, the formed structures can range from multiple partly unfolded protein molecules surrounding a single shared micelle to a single polypeptide chain decorating multiple micelles. We also have much new insight into how this species forms. It is preceded by the binding of small numbers of SDS molecules which subsequently grow by accretion. Time-resolved SAXS analysis reveals an asymmetric attack by SDS micelles followed by distribution of the increasingly unfolded protein around the micelle. The compactness of the protein chain continues to evolve at higher SDS concentrations according to single-molecule studies, though the protein remains completely denatured on the tertiary structural level. SDS denaturation can be reversed by addition of nonionic surfactants that absorb SDS forming mixed micelles, leaving the protein free to refold. Refolding can occur in parallel tracks if only a fraction of the protein is initially stripped of SDS. SDS unfolding is nearly always reversible unless carried out at low pH, where charge neutralization can lead to superclusters of protein-surfactant complexes. With the general mechanism of SDS denaturation now firmly established, it largely remains to explore how other ionic surfactants (including biosurfactants) may diverge from this path.
Topics: Micelles; Proteins; Scattering, Small Angle; Sodium Dodecyl Sulfate; Surface-Active Agents; X-Ray Diffraction
PubMed: 36027673
DOI: 10.1016/j.cis.2022.102754 -
Current Opinion in Structural Biology Dec 2023Proteins carry out the vast majority of functions in cells, but can only do so when properly folded. Following stress or mutation, proteins can lose their proper fold,... (Review)
Review
Proteins carry out the vast majority of functions in cells, but can only do so when properly folded. Following stress or mutation, proteins can lose their proper fold, resulting in misfolding, inactivity, and aggregation-posing a threat to cellular health. In order to counteract protein aggregation, cells have evolved a remarkable subset of molecular chaperones, called protein disaggregases, which collaboratively possess the ability to forcibly untangle protein aggregates. Here, we review the different chaperone disaggregation machineries present in the human cytosol and their mechanisms of action. Understanding, how these disaggregases function, is both universally and clinically important, as protein aggregation has been linked to multiple, debilitating neurodegenerative diseases.
Topics: Humans; HSP70 Heat-Shock Proteins; Cytosol; Protein Aggregates; Molecular Chaperones; Protein Folding
PubMed: 38000128
DOI: 10.1016/j.sbi.2023.102735 -
Chemical Society Reviews Oct 2020Mechanical forces regulate a large variety of cellular functionalities, encompassing e.g. motility, differentiation and muscle contractility. To adapt to the dynamic... (Review)
Review
Mechanical forces regulate a large variety of cellular functionalities, encompassing e.g. motility, differentiation and muscle contractility. To adapt to the dynamic change in mechanical stress, the constitutive individual proteins need to reversibly stretch and recoil over long periods of time. Yet, the molecular mechanisms controlling the mechanical unfolding and refolding of proteins cannot be accessed by protein folding biochemistry experiments conducted in the bulk, because they cannot typically apply forces to individual proteins. The advent of single-molecule nanomechanical techniques, often combined with bespoke protein engineering strategies, has enabled monitoring the conformational dynamics of proteins under force with unprecedented length-, time- and force-resolution. This review focuses on the fundamental operational principles of the main single-molecule nanomechanical techniques, placing particular emphasis on the most common analytical approaches used to extract information directly from the experiments. The breadth of enabling applications highlights the most exciting and promising outputs from the nanomechanics field to date.
Topics: Biomechanical Phenomena; Microscopy, Atomic Force; Nanotechnology; Optical Tweezers; Protein Engineering; Protein Folding; Proteins; Single Molecule Imaging; Spectrum Analysis
PubMed: 32929436
DOI: 10.1039/d0cs00426j -
Current Opinion in Structural Biology Feb 2024During protein synthesis, the growing nascent peptide chain moves inside the polypeptide exit tunnel of the ribosome from the peptidyl transferase center towards the... (Review)
Review
During protein synthesis, the growing nascent peptide chain moves inside the polypeptide exit tunnel of the ribosome from the peptidyl transferase center towards the exit port where it emerges into the cytoplasm. The ribosome defines the unique energy landscape of the pioneering round of protein folding. The spatial confinement and the interactions of the nascent peptide with the tunnel walls facilitate formation of secondary structures, such as α-helices. The vectorial nature of protein folding inside the tunnel favors local intra- and inter-molecular interactions, thereby inducing cotranslational folding intermediates that do not form upon protein refolding in solution. Tertiary structures start to fold in the lower part of the tunnel, where interactions with the ribosome destabilize native protein folds. The present review summarizes the recent progress in understanding the driving forces of nascent protein folding inside the tunnel and at the surface of the ribosome.
Topics: Protein Folding; Ribosomes; Protein Biosynthesis; Proteins; Peptides
PubMed: 38071940
DOI: 10.1016/j.sbi.2023.102740 -
Biological Chemistry Feb 2021Thiol-based redox switches evolved as efficient post-translational regulatory mechanisms that enable individual proteins to rapidly respond to sudden environmental... (Review)
Review
Thiol-based redox switches evolved as efficient post-translational regulatory mechanisms that enable individual proteins to rapidly respond to sudden environmental changes. While some protein functions need to be switched off to save resources and avoid potentially error-prone processes, protective functions become essential and need to be switched on. In this review, we focus on thiol-based activation mechanisms of stress-sensing chaperones. Upon stress exposure, these chaperones convert into high affinity binding platforms for unfolding proteins and protect cells against the accumulation of potentially toxic protein aggregates. Their chaperone activity is independent of ATP, a feature that becomes especially important under oxidative stress conditions, where cellular ATP levels drop and canonical ATP-dependent chaperones no longer operate. , reductive inactivation and substrate release require the restoration of ATP levels, which ensures refolding of client proteins by ATP-dependent foldases. We will give an overview over the different strategies that cells evolved to rapidly increase the pool of ATP-independent chaperones upon oxidative stress and provide mechanistic insights into how stress conditions are used to convert abundant cellular proteins into ATP-independent holding chaperones.
Topics: Molecular Chaperones; Oxidative Stress; Sulfhydryl Compounds
PubMed: 32990643
DOI: 10.1515/hsz-2020-0262 -
Journal of Molecular Biology Jun 2023Single-molecule force spectroscopy is a unique method that can probe the structural changes of single proteins at a high spatiotemporal resolution while mechanically... (Review)
Review
Single-molecule force spectroscopy is a unique method that can probe the structural changes of single proteins at a high spatiotemporal resolution while mechanically manipulating them over a wide force range. Here, we review the current understanding of membrane protein folding learned by using the force spectroscopy approach. Membrane protein folding in lipid bilayers is one of the most complex biological processes in which diverse lipid molecules and chaperone proteins are intricately involved. The approach of single protein forced unfolding in lipid bilayers has produced important findings and insights into membrane protein folding. This review provides an overview of the forced unfolding approach, including recent achievements and technical advances. Progress in the methods can reveal more interesting cases of membrane protein folding and clarify general mechanisms and principles.
Topics: Lipid Bilayers; Membrane Proteins; Microscopy, Atomic Force; Protein Folding; Spectrum Analysis; Single Molecule Imaging
PubMed: 37330286
DOI: 10.1016/j.jmb.2023.167975