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Instruments / Technical Area	Publication Details	Published
I22-Small angle scattering & Diffraction	Characterisation of a synthetic Archeal membrane reveals a possible new adaptation route to extreme conditions Marta Salvador-Castell , Maksym Golub , Nelli Erwin , Bruno Deme , Nicholas J. Brooks , Roland Winter , Judith Peters , Philippe Oger Communications Biology 4 DOI: 10.1038/s42003-021-02178-y Diamond Proposal Number(s): [23722] Open Access Show Abstract ▼ Abstract: 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-chemistry, extending its stability domain. Here, we have studied the effect of the apolar polyisoprenoid squalane on a model membrane analogue using neutron diffraction, SAXS and fluorescence spectroscopy. We show that squalane resides inside the bilayer midplane, extends its stability domain, reduces its permeability to protons but increases that of water, and induces a negative curvature in the membrane, allowing the transition to novel non-lamellar phases. This membrane architecture can be transposed to early membranes and could help explain their emergence and temperature tolerance if life originated near hydrothermal vents. Transposed to the archaeal bilayer, this membrane architecture could explain the tolerance to high temperature in hyperthermophiles which grow at temperatures over 100 °C while having a membrane bilayer. The induction of a negative curvature to the membrane could also facilitate crucial cell functions that require high bending membranes.	Jun 2021
I22-Small angle scattering & Diffraction	Impact of macromolecular crowding and compression on protein–protein interactions and liquid–liquid phase separation phenomena Karin Julius , Jonathan Weine , Mimi Gao , Jan Latarius , Mirko Elbers , Michael Paulus , Metin Tolan , Roland Winter Macromolecules DOI: 10.1021/acs.macromol.8b02476 Show Abstract ▼ Abstract: We determined the intermolecular interaction potential, V(r), of dense lysozyme solutions, which governs the spatial distribution of the protein molecules and the location of its liquid–liquid phase separation (LLPS) region, in various crowding environments applying small-angle X-ray scattering in combination with liquid-state theory. We explored the effect of polyethylene glycol (PEG) on V(r) and the protein’s phase behavior over a wide range of temperatures and pressures, crossing from the dilute to the semidilute polymer regime, thereby mimicking all crowding scenarios encountered in the heterogeneous biological cell. V(r) and hence the protein–protein distances and the phase boundary of the LLPS region strongly depend on the polymer-to-protein size ratio and the polymer concentration. The strongest effect is observed for small-sized PEG molecules, leading to a marked decrease of the mean intermolecular spacing of the protein molecules with increasing crowder concentration. The effect levels off at intermolecular distances where the proteins’ second hydration shells start to penetrate each other. Strong repulsive forces like hydration-shell repulsion and/or soft enthalpic protein-PEG interactions must be operative at short distances which stabilize the protein against depletion-induced aggregation, also at pressures as high as encountered in the deep sea, where pressures up to the kbar-level are encountered.	Feb 2019
I22-Small angle scattering & Diffraction	Water-mediated protein-protein interactions at high pressures are controlled by a deep-sea osmolyte Karin Julius , Jonathan Weine , Melanie Berghaus , Nico König , Mimi Gao , Jan Latarius , Michael Paulus , Martin A. Schroer , Metin Tolan , Roland Winter Physical Review Letters 121 DOI: 10.1103/PhysRevLett.121.038101 Diamond Proposal Number(s): [14949] Show Abstract ▼ Abstract: The influence of natural cosolvent mixtures on the pressure-dependent structure and protein-protein interaction potential of dense protein solutions is studied and analyzed using small-angle X-ray scattering in combination with a liquid-state theoretical approach. The deep-sea osmolyte trimethylamine-N-oxide is shown to play a crucial and singular role in its ability to not only guarantee sustainability of the native protein’s folded state under harsh environmental conditions, but it also controls water-mediated intermolecular interactions at high pressure, thereby preventing contact formation and hence aggregation of proteins.	Jul 2018
I22-Small angle scattering & Diffraction	On the origin of microtubules’ high-pressure sensitivity Mimi Gao , Melanie Berghaus , Simone Möbitz , Vitor Schuabb , Nelli Erwin , Marius Herzog , Karin Julius , Christian Sternemann , Roland Winter Biophysical Journal 114, 1080 - 1090 DOI: 10.1016/j.bpj.2018.01.021 Diamond Proposal Number(s): [14949] Show Abstract ▼ Abstract: For over 50 years, it has been known that the mitosis of eukaryotic cells is inhibited already at high hydrostatic pressure conditions of 30 MPa. This effect has been attributed to the disorganization of microtubules, the main component of the spindle apparatus. However, the structural details of the depolymerization and the origin of the pressure sensitivity have remained elusive. It has also been a puzzle how complex organisms could still successfully inhabit extreme high-pressure environments such as those encountered in the depth of oceans. We studied the pressure stability of microtubules at different structural levels and for distinct dynamic states using high-pressure Fourier-transform infrared spectroscopy and Synchrotron small-angle x-ray scattering. We show that microtubules are hardly stable under abyssal conditions, where pressures up to 100 MPa are reached. This high-pressure sensitivity can be mainly attributed to the internal voids and packing defects in the microtubules. In particular, we show that lateral and longitudinal contacts feature different pressure stabilities, and they define also the pressure stability of tubulin bundles. The intactness of both contact types is necessary for the functionality of microtubules in vivo. Despite being known to dynamically stabilize microtubules and prevent their depolymerization, we found that the anti-cancer drug taxol and the accessory protein MAP2c decrease the pressure stability of microtubule protofilaments. Moreover, we demonstrate that the cellular environment itself is a crowded place and accessory proteins can increase the pressure stability of microtubules and accelerate their otherwise highly pressure-sensitive de novo formation.	Mar 2018
I22-Small angle scattering & Diffraction	The effects of osmolytes and crowding on the pressure-induced dissociation and inactivation of dimeric LADH Karin Julius , Samy Ayoubi , Michael Paulus , Metin Tolan , Roland Winter Physical Chemistry Chemical Physics DOI: 10.1039/C7CP08242H Diamond Proposal Number(s): [14949] Show Abstract ▼ Abstract: Investigating the correlation between structure and activity of oligomeric enzymes at high pressure is essential for understanding intermolecular interactions and reactivity of proteins in cellulo of organisms thriving at extreme environmental conditions as well as for biotechnological applications, such as high-pressure enzymology. In a combined experimental effort employing small-angle X-ray scattering, FT-IR and fluorescence spectroscopy as well as stopped-flow enzyme kinetics in concert with high-pressure techniques, we reveal the pressure-induced conformational changes of the dimeric enzyme horse liver alcohol dehydrogenase (LADH) on the quaternary, secondary and tertiary structural level. Moreover, the effects of cosolutes and crowding agents, mimicking intracellular conditions, have been addressed. Our results show that beyond an increase of enzymatic activity at low pressures, loss of enzyme activity occurs around 600-800 bar, i.e. in a pressure regime where small conformational changes take place in the coenzyme's binding pocket, only. Whereas higher-order oligomers dissociate at low pressures, subunit dissociation of dimeric LADH takes place, depending on the solution conditions, between 2000 and 4000 bar, only. Oligomerization and subunit dissociation are modulated by cosolvents such as urea or trimethylamine-N-oxide as well as by the crowding agent polyethylene glycol, based on their tendency to bind to the protein's interface or act via their excluded volume effect, respectively.	Feb 2018
I22-Small angle scattering & Diffraction	Phase behavior of lysozyme solutions in the liquid–liquid phase coexistence region at high hydrostatic pressures Julian Schulze , Johannes Möller , Jonathan Weiner , Karin Julius , Nico König , Julia Nase , Michael Paulus , Metin Tolan , Roland Winter Physical Chemistry Chemical Physics DOI: 10.1039/C6CP01791F Show Abstract ▼ Abstract: We present results from small-angle X-ray scattering and turbidity measurements on the effect of high hydrostatic pressure on the phase behavior of dense lysozyme solutions in the liquid–liquid phase separation region, and characterize the underlying intermolecular protein–protein interactions as a function of temperature and pressure under charge-screening conditions (0.5 M NaCl). A reentrant liquid–liquid phase separation region is observed at elevated pressures, which may originate in the pressure dependence of the solvent-mediated protein–protein interaction. A temperature-pressure-concentration phase diagram was constructed for highly concentrated lysozyme solutions over a wide range of temperatures, pressures and protein concentrations including the critical region of the liquid–liquid miscibility gap.	May 2016
I22-Small angle scattering & Diffraction	Intermolecular interactions in highly concentrated protein solutions upon compression and the role of the solvent S. Grobelny , M. Erlkamp , J. Möller , M. Tolan , R. Winter The Journal Of Chemical Physics 141 (22) DOI: 10.1063/1.4895542 Show Abstract ▼ Abstract: The influence of high hydrostatic pressure on the structure and protein-protein interaction potential of highly concentrated lysozyme solutions up to about 370 mg ml−1 was studied and analyzed using small-angle X-ray scattering in combination with a liquid-state theoretical approach. In the concentration region below 200 mg ml−1, the interaction parameters of lysozyme solutions are affected by pressure in a nonlinear way, which is probably due to significant changes in the structural properties of bulk water, i.e., due to a solvent-mediated effect. Conversely, for higher concentrated protein solutions, where hydration layers below ∼4 water molecules are reached, the interaction potential turns rather insensitive to compression. The onset of transient (dynamic) clustering is envisaged in this concentration range. Our results also show that pressure suppresses protein nucleation, aggregation and finally crystallization in supersaturated condensed protein solutions. These findings are of importance for controlling and fine-tuning protein crystallization. Moreover, these results are also important for understanding the high stability of highly concentrated protein solutions (as they occur intracellularly) in organisms thriving under hydrostatic pressure conditions such as in the deep sea, where pressures up to the kbar-level are reached.	Dec 2014
I22-Small angle scattering & Diffraction	Specific anion effects on the pressure dependence of the protein-protein interaction potential Johannes Moeller , Sebastian Grobelny , Julian Schulze , Andre Steffen , Steffen Bieder , Michael Paulus , Metin Tolan , Roland Winter Physical Chemistry Chemical Physics 16 (16) DOI: 10.1039/c3cp55278k Diamond Proposal Number(s): [7976] Show Abstract ▼ Abstract: We present a study on ion specific effects on the intermolecular interaction potential V(r) of dense protein solutions under high hydrostatic pressure conditions. Small-angle X-ray scattering in combination with a liquid-state theoretical approach was used to determine the effect of structure breaking/making salt anions (Cl−, SO42−, PO43−) on the intermolecular interaction of lysozyme molecules. It was found that besides the Debye–Hückel charge screening effect, reducing the repulsiveness of the interaction potential V(r) at low salt concentrations, a specific ion effect is observed at high salt concentrations for the multivalent kosmotropic anions, which modulates also the pressure dependence of the protein–protein interaction potential. Whereas sulfate and phosphate strongly influence the pressure dependence of V(r), chloride anions do not. The strong structure-making effect of the multivalent anions, dominating for the triply charged PO43−, renders the solution structure less bulk-water-like at high salt concentrations, which leads to an altered behavior of the pressure dependence of V(r). Hence, the particular structural properties of the salt solutions are able to influence the spatial organization and the intermolecular interactions of the proteins, in particular upon compression. These results are of interest for exploring the combined effects of ionic strength, temperature and pressure on the phase behavior of protein solutions, but may also be of relevance for understanding pressure effects on the hydration behavior of biological matter under extreme environmental conditions.	Mar 2014
I22-Small angle scattering & Diffraction	The effects of pressure and temperature on the energetics and pivotal surface in a monoacylglycerol/water gyroid inverse bicontinuous cubic phase T.-Y. Dora Tang , Annela Seddon , Christoph Jeworrek , Roland Winter , Oscar Ces , John M. Seddon , Richard H. Templer Soft Matter 10 (17) DOI: 10.1039/c4sm00114a Open Access Show Abstract ▼ Abstract: We have studied the effect of pressure and temperature on the location of the pivotal surface in a lipid inverse bicontinuous gyroid cubic phase (QGII), described by the area at the pivotal surface (An), the volume between the pivotal surface and the bilayer midplane (Vn), and the molecular volume of the lipid (V). Small angle X-ray scattering (SAXS) was used to measure the swelling behaviour of the lipid, monolinolein, as a function of pressure and temperature, and the data were fitted to two different geometric models: the parallel interface model (PIM), and the constant mean curvature model (CMCM). The results show that an increase in temperature leads to a shift in the location of the pivotal surface towards the bilayer midplane, whilst an increase in pressure causes the pivotal surface to move towards the interfacial region. In addition, we describe the relevance of An, Vn and V for modeling the energetics of curved mesophases with specific reference to the mean curvature at the pivotal surface and discuss the significance of this parameter for modelling the energetics of curved mesophases.	Feb 2014
I22-Small angle scattering & Diffraction	Reentrant liquid-liquid phase separation in protein solutions at elevated hydrostatic pressures Johannes Moeller , Sebastian Grobelny , Julian Schulze , Steffen Bieder , Andre Steffen , Mirko Erlkamp , Michael Paulus , Metin Tolan , Roland Winter Physical Review Letters 112 (2), 028101 DOI: 10.1103/PhysRevLett.112.028101 PMID: 24484044 Diamond Proposal Number(s): [7976, 8604] Show Abstract ▼ Abstract: We present results from small-angle x-ray scattering data on the effect of high pressure on the phase behavior of dense lysozyme solutions in the liquid-liquid phase separation region, and characterize the underlying intermolecular protein-protein interactions as a function of temperature and pressure in this region of phase space. A reentrant liquid-liquid phase separation region has been discovered at elevated pressures, which originates in the pressure dependence of the solvent-mediated protein-protein interactions.	Jan 2014

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