Roland Winter's research while affiliated with Max Planck Institute for Biophysical Chemistry and other places

Publications (436)

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Because organisms living in the deep sea and in the subseafloor must be able to cope with hydrostatic pressures up to 1000 bar and more, their biomolecular processes, including ligand-binding...
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A high colloidal stability is important for pharmaceutical applications of antibody solutions. We demonstrate a high pressure sensitivity of antibody condensates as a suitable means to suppress liquid–liquid phase separation and subsequent aggregation of concentrated antibody solutions. The immunoglobulin molecules themselves are highly pressure re...
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High colloidal stability of antibody (immunoglobulin) solutions is important for pharmaceutical applications. Inert cosolutes, excipients, are generally used in therapeutic protein formulations to minimize physical instabilities, such as liquid‐liquid phase separation (LLPS), aggregation and precipitation, which are often encountered during manufac...
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Previous studies suggest that berberine, an isoquinoline alkaloid, has antiviral potential and is a possible therapeutic candidate against SARS-CoV-2. The molecular underpinnings of its action are still unknown. Potential targets include quadruplexes (G4Q) in the viral genome as they play a key role in modulating the biological activity of viruses....
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High pressure deep subsurface environments of Mars may harbor high concentrations of dissolved salts, such as perchlorates, yet we know little about how these salts influence the conditions for life, particularly in combination with high hydrostatic pressure. We investigated the effects of high magnesium perchlorate concentrations compared to sodiu...
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Previously, we characterized in detail the mechanism of action of the antimicrobial peptide GKY20, showing that it selectively perturbs the bacterial-like membrane employing peptide conformational changes, lipid segregation and domain formation as key steps in promoting membrane disruption. Here, we used a combination of biophysical techniques to s...
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One of the first steps in the origin of life was the formation of a membrane, a physical boundary that allowed the retention of molecules in concentrated solutions. The proto-membrane was likely formed by self-assembly of simple readily available amphiphiles, such as short-chain fatty acids and alcohols. In the commonly accepted scenario that life...
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Given the emergence of the severe acute respiratory syndrome‐coronavirus‐2 (SARS‐CoV‐2), which particularly threatens older people with comorbidities such as diabetes mellitus and dementia, understanding the relationship between Covid‐19 and other diseases is an important factor for treatment. Possible targets for medical intervention include G‐qua...
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Fluorescent RNA aptamers have the potential to enable routine quantitation and localization of RNA molecules, and serve as models for understanding biologically active aptamers. In recent years, several fluorescent aptamers have been selected and modified to improve their properties, revealing that small changes to the RNA or the ligands can modify...
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The interactions of ligands with nucleic acids are central to numerous reactions in the biological cell. How such reactions are affected by harsh environmental conditions such as low temperatures, high pressures, and high concentrations of destructive ions is still largely unknown. To elucidate the ions' role in shaping habitability in extraterrest...
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Archaeal lipids have harvested biomedical and biotechnological interest because of their ability to form membranes with low permeability and enhanced temperature and pressure stability. Because of problems in isolating archaeal lipids, chemical synthesis appears to be a suitable means of producing model lipids that mimic the biological counterparts...
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The application of co-solvents and high pressure has been shown to be an efficient means to modify the kinetics of enzyme-catalyzed reactions without compromising enzyme stability, which is often limited by temperature modulation. In this work, the high-pressure stopped-flow methodology was applied in conjunction with fast UV/Vis detection to inves...
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Studies of salt effects on enzyme activity have typically been conducted at standard temperatures and pressures, thus missing effects which only become apparent under non-standard conditions. Here we show that perchlorate salts, which are found pervasively on Mars, increase the activity of α-chymotrypsin at low temperatures. The low temperature act...
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Protein–ligand interactions are fundamental to all biochemical processes. Generally, these processes are studied at ambient temperature and pressure conditions. We investigated the binding of the small ligand 8-anilinonaphthalene-1-sulfonic acid (ANS) to the multifunctional protein bovine serum albumin (BSA) at ambient and low temperatures and at h...
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The intrinsically disordered protein α-synuclein causes Parkinson’s disease by forming toxic oligomeric aggregates inside neurons. Single-molecule FRET experiments revealed conformational changes of noncanonical DNA structures, such as i-motifs and hairpins,...
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Liquid–liquid phase separation plus the droplet formation of proteins has emerged as a key mechanism for intracellular organization, but there is also evidence linking it to a variety of medical conditions. Pathological aggregation of α‐synuclein, which is causally linked to Parkinson's disease, can proceed via such droplet condensation. We show th...
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Lipid membranes are a key component of contemporary living systems and are thought to have been essential to the origin of life. Most research on membranes has focused on situations restricted to ambient physiological or benchtop conditions. However, the influence of more extreme conditions, such as the deep subsurface on Earth or extraterrestrial...
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The modification of archaeal lipid bilayer properties by the insertion of apolar molecules in the lipid bilayer midplane has been proposed to support cell membrane adaptation to extreme environmental conditions of temperature and hydrostatic pressure. In this work, we characterize the insertion effects of the apolar polyisoprenoid squalane on the p...
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It has been proposed that adaptation to high temperature involved the synthesis of monolayer-forming ether phospholipids. Recently, a novel membrane architecture was proposed to explain the membrane stability in polyextremophiles unable to synthesize such lipids, in which apolar polyisoprenoids populate the bilayer midplane and modify its physico-c...
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Formation of biomolecular condensates through liquid-liquid phase separation (LLPS) has been described for several pathogenic proteins linked to neurodegenerative diseases and is discussed as an early step in the formation of protein aggregates with neurotoxic properties. In prion diseases, neurodegeneration and formation of infectious prions is ca...
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Liquid‐liquid phase separation (LLPS) has emerged as a key mechanism for intracellular organization, and many recent studies have provided important insights into the role of LLPS in cell biology. There is also evidence that LLPS is associated with a variety of medical conditions, including neurodegenerative disorders. Pathological aggregation of α...
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The development of DNA‐compatible reactions is central to advance DNA‐encoded library technology. Amphiphilic block copolymer micelles functionalized with sulfonic acid moieties assemble in water to micelles and localize the catalyst in them. DNA‐aldehyde conjugates were reacted to target heterocycles by micelle‐promoted Povarov‐ and Biginelli‐reac...
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The development of DNA‐compatible reaction methodologies is a central theme to advance DNA‐encoded screening library technology. Recently, we could show that sulfonic acid functionalized block copolymer micelles facilitated Brønsted acid promoted reactions such as the Povarov reaction on DNA‐coupled starting materials with minimal DNA degradation....
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Recently, non-canonical DNA structures, such as G-quadruplexes (GQs), were found to be highly pressure sensitive, suggesting that pressure modulation studies can provide additional mechanistic details of such biomolecular systems. Using FRET and CD spectroscopy as well as binding equilibrium measurements, we investigated the effect of pressure on t...
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Biomolecular condensates formed by liquid-liquid phase separation (LLPS) are considered one of the early compartmentalization strategies of cells, which still prevail today forming nonmembranous compartments in biological cells. Studies of the effect of high pressures, such as those encountered in the subsurface salt lakes of Mars or in the depths...
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Lasioglossin III (LL-III) is a cationic antimicrobial peptide derived from the venom of the eusocial bee Lasioglossum laticeps. LL-III is extremely toxic to both Gram-positive and Gram-negative bacteria, and it exhibits antifungal as well as antitumor activity. Moreover, it shows low hemolytic activity, and it has almost no toxic effects on eukaryo...
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Liquid-liquid phase separation has been shown to promote the formation of functional membraneless organelles involved in various cellular processes, including metabolism, stress response and signal transduction. Protein LAF1 found in P-granules phase separates into liquid-like droplets by patterned electrostatic interactions between acidic and basi...
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Various studies have described remarkable biological activities and surface-active properties of rhamnolipids, leading to their proposed use in a wide range of industrial applications. Here, we report on a study of the effects of monorhamnolipid RhaC10C10 and dirhamnolipid RhaRhaC10C10 incorporation into model membranes of varying complexity, inclu...
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A comprehensive understanding of ligand–protein interactions requires information about all thermodynamic parameters that describe the complexation reaction, and they should be able to provide the necessary information to understand the molecular forces that drive complex formation. Usually, binding studies are performed at ambient pressure conditi...
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Our understanding of the amyloid structures of and the mechanisms by which disease-associated peptides and proteins self-assemble into these fibrillar aggregates, has advanced considerably in recent years. It is also established that amyloid fibrils are generally polymorphic. The molecular structures of the aggregation intermediates and the causes...
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Research on Parkinson's disease most often focuses on the ability of the protein α-synuclein (α-syn) to form oligomers and amyloid fibrils, and how such species promote brain death. However, there are indications that α-syn also plays a gene-regulatory role in the cell nucleus. Noncanonical tetrahelical nucleic acids, G-quadruplexes (G4Q), and i-mo...
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Biomolecular assembly processes based on liquid–liquid phase separation (LLPS) are ubiquitous in the biological cell. To fully understand the role of LLPS in biological self-assembly, it is necessary to characterize also their kinetics of formation and dissolution. Here, we introduce the pressure-jump relaxation technique in concert with UV/Vis and...
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Deep subsurface environments can harbour high concentrations of dissolved ions, yet we know little about how this shapes the conditions for life. We know even less about how the combined effects of high pressure influence the way in which ions constrain the possibilities for life. One such ion is perchlorate, which is found in extreme environments...
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Broad-spectrum antivirals are powerful weapons against dangerous viruses where no specific therapy exists, as in the case of the ongoing SARS-CoV-2 pandemic. We discovered that a lysine- and arginine-specific supramolecular ligand (CLR01) destroys enveloped viruses, including HIV, Ebola and Zika virus, and remodels amyloid fibrils in semen that pro...
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In recent years, liquid-liquid phase separation (LLPS) has emerged as a key mechanism for intracellular organization. But there is rapidly growing evidence that LLPS may also be associated with a number of medical conditions, including neurodegenerative diseases, by acting as a modulator of pathological protein aggregation. Here we show how LLPS fo...
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The use of cosolutes and high hydrostatic pressure has been described as an efficient means to modulate the stability of enzymes and their catalytic activity. Cosolvents and pressure can lead to increased reaction rates without compromising the stability of the enzyme. Inspired by the multi‐component nature of the crowded cellular milieu of biologi...
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Rhamnolipids represent a large class of biologically produced surface-active compounds, which participate in various essential cellular functions. While many studies have reported on the antibacterial and antifungal effects of rhamnolipids, only a few tried to describe the molecular mechanisms underlying these effects. Here, we first review the lit...
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The use of cosolvents and high hydrostatic pressure (HHP) has been described as an efficient means to modulate the stability of enzymes and their catalytic activity. Cosolvents and pressure can lead to increased reaction rates without affecting the stability of the enzyme. Here, we studied the combined effects of one of the most used organic cosolv...
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A novel, dicationic imidazolium salt is described and investigated towards its application for gene transfer. The polar head group and the long alkyl chains in the backbone contribute to a lipid‐like behavior, while an alkyl ammonium group provides the ability for crucial electrostatic interaction for the transfection process. Detailed biophysical...
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A binary protein condensate that mimics postsynaptic densities revealed high pressure sensitivity. This may help to gain a better understanding of the biophysical causes of pressure‐related neurological disorders, such as the high‐pressure neurological syndrome experienced by deep‐sea divers. More information can be found in the Full Paper by R. Wi...
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Interactions between proteins and ligands, which are fundamental to many biochemical processes essential to life, are mostly studied at dilute buffer conditions. The effects of the highly crowded nature of biological cells and the effects of liquid-liquid phase separation inducing biomolecular droplet formation as a means of membrane-less compartme...
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Activation of Raf kinases by the membrane-anchored protein K-Ras4B is a key step of cellular signal regulation. As a predominant variant of the Ras family, K-Ras4B has been considerated a major drug target in cancer therapy. Therefore, an intergrated study of Raf interaction with membane-associated K-Ras4B is essential. While the Ras-binding domain...
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The arginine binding protein from T. maritima (ArgBP) exhibits several distinctive biophysical and structural properties. Here we show that ArgBP is also endowed with a remakable pressure stability as it...
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We studied the effect of an amyloidogenic intrinsically disordered protein, α‐synuclein, which is associated with Parkinson's disease (PD), on the conformational dynamics of a DNA hairpin (DNA‐HP) employing the single‐molecule Förster resonance energy transfer method. The open‐to‐closed conforma­tional equilibrium of the DNA‐HP is drastically affec...
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In recent years, alkylated imidazolium salts have been shown to affect lipid membranes and exhibit general cytotoxicity as well as significant anti-tumor activity. Here, we examined the interactions of a sterically demanding, biophysically unexplored imidazolium salt, 1,3-bis(2,6-diisopropylphenyl)-4,5-diundecylimidazolium bromide (C11IPr), on the...
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The chaperonin system GroEL-GroES is present in all kingdoms of life and rescues proteins from improper folding and aggregation upon internal and external stress conditions, including high temperatures and pressures. Here, we set out to explore the thermo- and barostability of GroEL, GroES and the GroEL-GroES complex in the presence of cosolvents,...
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Biomolecular condensates consisting of proteins and nucleic acids can serve critical biological functions—so much so that some condensates are referred as membrane‐less organelles. They can also be disease‐causing if their assembly is misregulated. A major physico‐chemical basis of the formation of biomolecular condensates is liquid‐liquid phase se...
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Type 2 diabetes (T2DM) is associated with aggregation of the human islet amyloid polypeptide (hIAPP) into cytotoxic amyloid species. Here we tested the effect of a diphenylpyrazole (DPP)-derived small molecule inhibitor, anle145c, on cytotoxicity and on aggregation properties of hIAPP. We demonstrate that incubation of hIAPP with the inhibitor yiel...
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We studied the combined effects of an aqueous two-phase system (ATPS) invoking liquid-liquid phase separation and pressure on an enzymatic hydrolysis reaction. We show that simple steric crowding effects are not able to explain the kinetic constants and their pressure dependence in the ATPS. Additional contributions, such as changes in water activi...
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The application of co-solvents and high pressure has been reported to be an efficient means to tune the kinetics of enzyme-catalyzed reactions. Co-solvents and pressure can lead to increased reaction rates without sacrificing enzyme stability, while temperature and pH operation windows are generally very narrow. Quantitative prediction of co-solven...
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Biological functions of proteins are underpinned by physicochemical processes governed by the intra‐ and intermolecular interactions among proteins and other biomolecules. Understanding these interactions is important not only for deciphering normal biological functions but also for gaining insights into disease processes as well as for biotechnolo...
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Reversible S-palmitoylation is a key regulatory mechanism of protein function and localization. There is increasing evidence that S-acylation is not restricted to palmitate but it includes shorter, longer, and unsaturated fatty acids. However, the diversity of this protein modification has not been fully explored. Herein, we report a chemical probe...
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Using all-atom molecular dynamics simulations of aqueous solutions of the globular protein SNase, the dynamic behavior of water molecules and cosolvents (trimethylamine-N-oxide (TMAO) and urea) in the hydration shell of the protein was studied for different solvent compositions. TMAO is a potent protein-stabilizing osmolyte, whereas urea is known t...
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We used single-molecule FRET experiments to deduce the conformational equilibrium of a DNA hairpin under pressure-stress in the presence of an aqueous two-phase system mimicking intracellular liquid-liquid phase separation (LLPS)....
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We studied the interaction of lipid membranes with the deap-sea osmolyte trimethalamine-N-oxid (TMAO), which is known to stabilize proteins most efficiently against various environmental stress factors, including high hydrostatic pressure (HHP). Small-angle X-ray-scattering was applied in combination with fluorescence and infrared spectroscopy, cal...
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Recent methodological progress in quantum-chemical calculations using the "embedded cluster reference interaction site model" (EC-RISM) integral equation theory is reviewed in the context of applying it as a solvation model for calculating pressure-dependent thermodynamic and spectroscopic properties of molecules immersed in water. The methodology...
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The pharmacological application of antimicrobial peptides (AMPs) is seriously limited as they are not chemically and physically stable. Their encapsulation could represent a way to protect AMPs improving their pharmacological properties. In this study, the complex between the sulfobutylether-β-cyclodextrin (SBE-β-CD) and the antimicrobial peptide (...
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Autophagy mediates the degradation of damaged proteins, organelles and pathogens, and plays a key role in health and disease. Thus, the identification of new mechanisms involved in the regulation of autophagy is of major interest. In particular, little is known about the role of lipids and lipid-binding proteins in the early steps of autophagosome...
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The intrinsically disordered human islet amyloid polypeptide (hIAPP) is a 37 amino acid peptide hormone that is secreted by pancreatic beta cells along with glucagon and insulin. The glucose metabolism of humans is regulated by a balanced ratio of insulin and hIAPP. The disturbance of this balance can result in the development of type-2 diabetes me...
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Liquid‐liquid phase separation (LLPS) of proteins and other biomolecules plays critical roles in the organization of extracellular materials and membrane‐less compartmentalization of intra‐organismal space through the formation of condensates. Structural properties of such mesoscopic droplet‐like states were studied by spectroscopy, microscopy, and...
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One of the grand challenges of biophysical chemistry is to understand the principles that govern protein misfolding and aggregation, which is a highly complex process that is sensitive to initial conditions, operates on a huge range of length- and timescales, and has products that range from protein dimers to macroscopic amyloid fibrils. Aberrant a...
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Thermodynamics and kinetics of biochemical reactions depend not only on temperature, but also on pressure and on the presence of cosolvents in the reaction medium. Understanding their effects on biochemical processes is a crucial step towards the design and optimization of industrially relevant enzymatic reactions. Such reactions typically do not t...
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Oncogenic Ras mutations occur in more than 30% of human cancers. K‐Ras4B is the most frequently mutated isoform of Ras proteins. Development of effective K‐Ras4B inhibitors has been challenging, hence new approaches to inhibit this oncogenic protein are urgently required. The polybasic domain of K‐Ras4B with its stretch of lysine residues is essent...