Exploring the temperature–pressure configurational landscape of biomolecules: from lipid membranes to proteins

2004 ◽  
Vol 363 (1827) ◽  
pp. 537-563 ◽  
Author(s):  
R. Winter ◽  
W. Dzwolak
Keyword(s):  
High Pressure ◽  
Lipid Membranes ◽  
Phase Behaviour ◽  
Pressure Jump ◽  
Spectroscopic Techniques ◽  
Biomolecular Systems ◽  
Time Resolved ◽  
Temperature And Pressure ◽  
Pressure Jump Relaxation ◽  
The Stability

Hydrostatic pressure has been used as a physical parameter for studying the stability and energetics of biomolecular systems, such as lipid mesophases and proteins, but also because high pressure is an important feature of certain natural membrane environments and because the high–pressure phase behaviour of biomolecules is of biotechnological interest. By using spectroscopic and scattering techniques, the temperature– and pressure–dependent structure and phase behaviour of lipid systems, differing in chain configuration, headgroup structure and concentration, and proteins have been studied and are discussed. A thermodynamic approach is presented for studying the stability of proteins as a function of both temperature and pressure. The results demonstrate that combined temperature–pressure dependent studies can help delineate the free–energy landscape of proteins and hence help elucidate which features and thermodynamic parameters are essential in determining the stability of the native conformational state of proteins. We also introduce pressure as a kinetic variable. Applying the pressure jump relaxation technique in combination with time–resolved synchrotron X–ray diffraction and spectroscopic techniques, the kinetics of un/refolding of proteins has been studied. Finally, recent advances in using pressure for studying misfolding and aggregation of proteins will be discussed.

Pressure effects on the structure of lyotropic lipid mesophases and model biomembrane systems

2000 ◽  
Vol 215 (8) ◽  
Author(s):  
Roland Winter ◽  
C. Czeslik
Keyword(s):  
High Pressure ◽  
Phase Behavior ◽  
Pressure Effects ◽  
Model Systems ◽  
Lipid Phase ◽  
Pressure Jump ◽  
Time Resolved ◽  
X Ray ◽  
High Pressure Phase Behavior ◽  
Temperature And Pressure

Lipid systems, which provide valuable model systems for biological membranes, display a variety of polymorphic phases, depending on their molecular structure and environmental conditions. By use of X-ray and neutron diffraction the temperature- and pressure-dependent structure and phase behavior of lipid systems, differing in chain configuration and headgroup structure, have been studied. Besides lamellar phases also nonlamellar phases have been investigated. Hydrostatic pressure has been used as a physical parameter for studying the stability and energetics of lyotropic lipid mesophases, but also because high pressure is an important feature of certain natural membrane environments (e.g., marine biotopes) and because the high pressure phase behavior of biomolecules is of biotechnological interest (e.g., high pressure food processing). We demonstrate that temperature and pressure have noncongruent effects on the structural and phase behavior. By using the pressure-jump relaxation technique in combination with time-resolved synchrotron X-ray diffraction, the kinetics of different lipid phase transformations was also investigated. The time constants for completion of the transitions depend on the direction of the transition, the symmetry and topology of the structures involved, and also on the pressure-jump amplitude. In addition, the effect of incorporating ions, steroids and polypeptides into bilayers on the temperature- and pressure-dependent phase behavior of the lipid systems is discussed.

High Pressure X-ray Studies of Lipid Membranes and Lipid Phase Transitions

2014 ◽  
Vol 228 (10-12) ◽  
Author(s):  
Nicholas J. Brooks ◽  
John M. Seddon
Keyword(s):  
High Pressure ◽  
Phase Transitions ◽  
Lipid Membranes ◽  
Soft Matter ◽  
Lipid Membrane ◽  
Lipid Phase ◽  
Pressure Jump ◽  
X Ray ◽  
Lipid Phase Transitions ◽  
X Ray Scattering

AbstractHydrostatic pressure has dramatic effects on biomembrane structure and stability and is a key thermodynamic parameter in the context of the biology of deep sea organisms. Furthermore, high-pressure and pressure-jump studies are very useful tools in biophysics and biotechnology, where they can be used to study the mechanism and kinetics of lipid phase transitions, biomolecular transformations, and protein folding/unfolding. Here, we first give an overview of the technology currently available for X-ray scattering studies of soft matter systems under pressure. We then illustrate the use of this technology to study a variety of lipid membrane systems.

scholarly journals The effects of cosolutes and crowding on the kinetics of protein condensate formation based on liquid–liquid phase separation: a pressure-jump relaxation study

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Hasan Cinar ◽  
Roland Winter
Keyword(s):  
Phase Separation ◽  
Liquid Phase ◽  
Liquid Phase Separation ◽  
Pressure Jump ◽  
Transformation Kinetics ◽  
Biologically Relevant ◽  
Pressure Jump Relaxation ◽  
The Stability ◽  
Kinetics Of ◽  
Liquid Liquid Phase Separation

Abstract 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 FTIR spectroscopy as well as light microscopy to characterize the evolution of LLPS formation and dissolution in a time-dependent manner. As a model system undergoing LLPS we used the globular eye-lens protein γD-crystallin. As cosolutes and macromolecular crowding are known to affect the stability and dynamics of biomolecular condensates in cellulo, we extended our kinetic study by addressing also the impact of urea, the deep-sea osmolyte trimethylamine-N-oxide (TMAO) and a crowding agent on the transformation kinetics of the LLPS system. As a prerequisite for the kinetic studies, the phase diagram of γD-crystallin at the different solution conditions also had to be determined. The formation of the droplet phase was found to be a very rapid process and can be switched on and off on the 1–4 s timescale. Theoretical treatment using the Johnson–Mehl–Avrami–Kolmogorov model indicates that the LLPS proceeds via a diffusion-limited nucleation and growth mechanism at subcritical protein concentrations, a scenario which is also expected to prevail within biologically relevant crowded systems. Compared to the marked effect the cosolutes take on the stability of the LLPS region, their effect at biologically relevant concentrations on the phase transformation kinetics is very small, which might be a particular advantage in the cellular context, as a fast switching capability of the transition should not be compromised by the presence of cellular cosolutes.

Interrogating the Structural Dynamics and Energetics of Biomolecular Systems with Pressure Modulation

2019 ◽  
Vol 48 (1) ◽  
pp. 441-463 ◽  
Author(s):  
Roland Winter
Keyword(s):  
Structural Dynamics ◽  
Structural Transformations ◽  
Pressure Jump ◽  
Enzymatic Reactions ◽  
Biomolecular Systems ◽  
Dynamical Properties ◽  
Relaxation Studies ◽  
Pressure Modulation ◽  
Pressure Jump Relaxation ◽  
Key Parameter

High hydrostatic pressure affects the structure, dynamics, and stability of biomolecular systems and is a key parameter in the context of the exploration of the origin and the physical limits of life. This review lays out the conceptual framework for exploring the conformational fluctuations, dynamical properties, and activity of biomolecular systems using pressure perturbation. Complementary pressure-jump relaxation studies are useful tools to study the kinetics and mechanisms of biomolecular phase transitions and structural transformations, such as membrane fusion or protein and nucleic acid folding. Finally, the advantages of using pressure to explore biomolecular assemblies and modulate enzymatic reactions are discussed.

High-Pressure Effects on the Structure and Phase Behavior of Model Membrane Systems

1996 ◽  
Author(s):  
Roland Winter ◽  
Anne Landwehr
Keyword(s):  
High Pressure ◽  
Phase Behavior ◽  
Lipid Bilayers ◽  
Lipid Membranes ◽  
Membrane Lipids ◽  
Pressure Effects ◽  
Scanning Calorimetry ◽  
Hydrocarbon Chains ◽  
Temperature And Pressure ◽  
Lipid Conformation

Phospholipids, which provide valuable model systems for lipid membranes, display a variety of polymorphic phases, depending on their molecular structure and on environmental conditions. High hydrostatic pressure has been used as a physical parameter to study the thermodynamic properties and phase behavior of these systems. High pressure is also a characteristic feature of certain natural membrane environments. In the first part of this article, we review our recent work on the temperature- and pressure-dependent phase behavior of phospholipid systems differing in lipid conformation and headgroup structure. In the second part, we report on the determination of the (T, x, p) phase diagrams of binary phospholipid mixtures. An additional section deals with effects of incorporating ions, small amphiphilic molecules, and steroids into the bilayer on the experimental temperature- and pressure-dependent phase behavior of lipid systems. Finally, we discuss lamellar to nonlamellar thermotropic and barotropic phase transformations, which occur for a number of lipids, such as phosphatidylethanolamines, monoacylglycerides, and lipid mixtures. It has been suggested that nonlamellar lipid structures might play an important role as transient and local intermediates in a number of biochemical processes. High-pressure smallangle x-ray (SAXS) and neutron (SANS) scattering, differential scanning calorimetry (DSC), high-pressure differential thermal analysis (DTA), and p, V, T measurements have been used as experimental methods for the investigation of these systems. Lipid bilayer dispersions, in particular the phosphatidylcholines and phosphatidylethanolamines, are the workhorses for the investigation of biophysical properties of membrane lipids because they constitute the basic structural component of biological membranes. They exhibit a rich lyotropic and thermotropic phase behavior (Cevc & Marsh, 1987; Marsh, 1991; Yeagle, 1992). Most fully hydrated saturated phospholipid bilayers exhibit two principal thermotropic lamellar phase transitions, corresponding to a gel to gel (Lβ′–Pβ′) transition and a gel to liquid-crystalline (Pβ′–Lα) main transition at a temperature Tm. In the fluid-like La phase, the hydrocarbon chains of the lipid bilayers are conformationally disordered, whereas in the gel phases the hydrocarbon chains are more extended and relatively ordered.

Effects of the deep-sea osmolyte TMAO on the temperature and pressure dependent structure and phase behavior of lipid membranes

2019 ◽  
Vol 21 (34) ◽  
pp. 18533-18540 ◽  
Author(s):  
Magiliny Manisegaran ◽  
Steffen Bornemann ◽  
Irena Kiesel ◽  
Roland Winter
Keyword(s):  
High Pressure ◽  
Phase Behavior ◽  
Deep Sea ◽  
Lipid Membranes ◽  
Temperature And Pressure ◽  
Lateral Organization

The deep-sea osmolyte TMAO does not only stabilize proteins against high pressure, it affects also the fluidity and lateral organization of membranes.

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