New opportunities for time-resolved imaging using diffraction-limited storage rings.

The advent of diffraction-limited storage rings (DLSRs) has boosted the brilliance or coherent flux by one to two orders of magnitude with respect to the previous generation. One consequence of this brilliance enhancement is an increase in the flux density or number of photons per unit of area and time, which opens new possibilities for the spatiotemporal resolution of X-ray imaging techniques. This paper studies the time-resolved microscopy capabilities of such facilities by benchmarking the ForMAX beamline at the MAX IV storage ring.

Stabilization of Non-Native Folds and Programmable Protein Gelation in Compositionally Designed Deep Eutectic Solvents.

Proteins are adjustable units from which biomaterials with designed properties can be developed. However, non-native folded states with controlled topologies are hardly accessible in aqueous environments, limiting their prospects as building blocks. Here, we demonstrate the ability of a series of anhydrous deep eutectic solvents (DESs) to precisely control the conformational landscape of proteins.

Synthesis of Well-Ordered Functionalized Silicon Microwires Using Displacement Talbot Lithography for Photocatalysis.

Metal-assisted chemical etching (MACE) is a cheap and scalable method that is commonly used to obtain silicon nano- or microwires but lacks spatial control. Herein, we present a synthesis method for producing vertical and highly periodic silicon microwires, using displacement Talbot lithography before wet etching with MACE. The functionalized periodic silicon microwires show 65% higher PEC performance and 2.

Molecular basis for human aquaporin inhibition.

Cancer invasion and metastasis are known to be potentiated by the expression of aquaporins (AQPs). Likewise, the expression levels of AQPs have been shown to be prognostic for survival in patients and have a role in tumor growth, edema, angiogenesis, and tumor cell migration. Thus, AQPs are key players in cancer biology and potential targets for drug development.

Exploring the Role of Globular Domain Locations on an Intrinsically Disordered Region of p53: A Molecular Dynamics Investigation.

The pre-tetramerization loop (PTL) of the human tumor suppressor protein p53 is an intrinsically disordered region (IDR) necessary for the tetramerization process, and its flexibility contributes to the essential conformational changes needed. Although the IDR can be accurately simulated in the traditional manner of molecular dynamics (MD) with the end-to-end distance (EE) unhindered, we sought to explore the effects of restraining the EE to the values predicted by electron microscopy (EM) and other distances. Simulating the PTL trajectory with a restrained EE , we found an increased agreement of nuclear magnetic resonance (NMR) chemical shifts with experiments.

The intracellular helical bundle of human glucose transporter GLUT4 is important for complex formation with ASPL.

Glucose transporters (GLUTs) are responsible for transporting hexose molecules across cellular membranes. In adipocytes, insulin stimulates glucose uptake by redistributing GLUT4 to the plasma membrane. In unstimulated adipose-like mouse cell lines, GLUT4 is known to be retained intracellularly by binding to TUG protein, while upon insulin stimulation, GLUT4 dissociates from TUG.

Using Cluster Theory to Calculate the Experimental Structure Factors of Antibody Solutions.

Monoclonal antibody solutions are set to become a major therapeutic tool in the years to come, capable of targeting various diseases by clever design of their antigen binding site. However, the formulation of stable solutions suitable for patient self-administration typically presents challenges, as a result of the increase in viscosity that often occurs at high concentrations. Here, we establish a link between the microscopic molecular details and the resulting properties of an antibody solution through the characterization of clusters, which arise in the presence of self-associating antibodies.

Cryo-EM structure supports a role of AQP7 as a junction protein.

Aquaglyceroporin 7 (AQP7) facilitates glycerol flux across the plasma membrane with a critical physiological role linked to metabolism, obesity, and associated diseases. Here, we present the single-particle cryo-EM structure of AQP7 determined at 2.55 Å resolution adopting two adhering tetramers, stabilized by extracellularly exposed loops, in a configuration like that of the well-characterized interaction of AQP0 tetramers.

Dip-and-pull ambient pressure photoelectron spectroscopy as a spectroelectrochemistry tool for probing molecular redox processes.

Ambient pressure x-ray photoelectron spectroscopy (APXPS) can provide a compelling platform for studying an analyte's oxidation and reduction reactions in solutions. This paper presents proof-of-principle operando measurements of a model organometallic complex, iron hexacyanide, in an aqueous solution using the dip-and-pull technique. The data demonstrates that the electrochemically active liquid meniscuses on the working electrodes can undergo controlled redox reactions which were observed using APXPS.

Probing Cage Relaxation in Concentrated Protein Solutions by X-Ray Photon Correlation Spectroscopy.

Diffusion of proteins on length scales of their size is crucial for understanding the machinery of living cells. X-ray photon correlation spectroscopy (XPCS) is currently the only way to access long-time collective diffusion on these length scales, but radiation damage so far limits the use in biological systems. We apply a new approach to use XPCS to measure cage relaxation in crowded α-crystallin solutions.

Hydration in Deep Eutectic Solvents Induces Non-monotonic Changes in the Conformation and Stability of Proteins.

The preservation of labile biomolecules presents a major challenge in chemistry, and deep eutectic solvents (DESs) have emerged as suitable environments for this purpose. However, how the hydration of DESs impacts the behavior of proteins is often neglected. Here, we demonstrate that the amino acid environment and secondary structure of two proteins (bovine serum albumin and lysozyme) and an antibody (immunoglobulin G) in 1:2 choline chloride:glycerol and 1:2 choline chloride:urea follow a re-entrant behavior with solvent hydration.

Molecular dynamics simulations of the adsorption of an intrinsically disordered protein: Force field and water model evaluation in comparison with experiments.

This study investigates possible structural changes of an intrinsically disordered protein (IDP) when it adsorbs to a solid surface. Experiments on IDPs primarily result in ensemble averages due to their high dynamics. Therefore, molecular dynamics (MD) simulations are crucial for obtaining more detailed information on the atomistic and molecular levels.

The Design of 3D-Printed Polylactic Acid-Bioglass Composite Scaffold: A Potential Implant Material for Bone Tissue Engineering.

Bio-based and patient-specific three-dimensional (3D) scaffolds can present next generation strategies for bone tissue engineering (BTE) to treat critical bone size defects. In the present study, a composite filament of poly lactic acid (PLA) and 45S5 bioglass (BG) were used to 3D print scaffolds intended for bone tissue regeneration. The thermally induced phase separation (TIPS) technique was used to produce composite spheres that were extruded into a continuous filament to 3D print a variety of composite scaffolds.

Anisotropic protein-protein interactions in dilute and concentrated solutions.

Interactions between biomolecules are ubiquitous in nature and crucial to many applications including vaccine development; environmentally friendly textile detergents; and food formulation. Using small angle X-ray scattering and structure-based molecular simulations, we explore protein-protein interactions in dilute to semi-concentrated protein solutions. We address the pertinent question, whether interaction models developed at infinite dilution can be extrapolated to concentrated regimes? Our analysis is based on measured and simulated osmotic second virial coefficients and solution structure factors at varying protein concentration and for different variants of the protein Thermomyces Lanuginosus Lipase (TLL).

Extending depolarized DLS measurements to turbid samples.

The application of dynamic light scattering to soft matter systems has strongly profited from advanced approaches such as the so-called modulated 3D cross correlation technique (Mod3D-DLS) that suppress contributions from multiple scattering, and can therefore be used for the characterization of turbid samples. Here we now extend the possibilities of this technique to allow for depolarized light scattering (Mod3D-DDLS) and thus obtain information on both translational and rotational diffusion, which is important for the characterization of anisotropic particles. We describe the required optical design and test the performance of the approach for increasingly turbid samples using well defined anisotropic colloidal models systems.

The scale of a martian hydrothermal system explored using combined neutron and x-ray tomography.

Nakhlite meteorites are igneous rocks from Mars that were aqueously altered ~630 million years ago. Hydrothermal systems on Earth are known to provide microhabitats; knowledge of the extent and duration of these systems is crucial to establish whether they could sustain life elsewhere in the Solar System. Here, we explore the three-dimensional distribution of hydrous phases within the Miller Range 03346 nakhlite meteorite using nondestructive neutron and x-ray tomography to determine whether alteration is interconnected and pervasive.

3D-printed monolithic biofilters based on a polylactic acid (PLA) - hydroxyapatite (HAp) composite for heavy metal removal from an aqueous medium.

High flux, monolithic water purification filters based on polylactic acid (PLA) functionalised with fish scale extracted hydroxyapatite (HAp) were prepared by solvent-assisted blending and thermally induced phase separation (TIPS), followed by twin-screw extrusion into filaments and processed three-dimensional (3D) printing. The printed filters with consistent pore geometry and channel interconnectivity as well as homogenous distribution of HAp in the PLA matrix showed adsorption capabilities towards heavy metals cadmium (Cd) and lead (Pb) with maximum adsorption capacity of 112.1 mg g and 360.

Effect of encapsulated protein on the dynamics of lipid sponge phase: a neutron spin echo and molecular dynamics simulation study.

Lipid membranes are highly mobile systems with hierarchical, time and length scale dependent, collective motions including thickness fluctuations, undulations, and topological membrane changes, which play an important role in membrane interactions. In this work we have characterised the effect of encapsulating two industrially important enzymes, β-galactosidase and aspartic protease, in lipid sponge phase nanoparticles on the dynamics of the lipid membrane using neutron spin echo (NSE) spectroscopy and molecular dynamics (MD) simulations. From NSE, reduced membrane dynamics were observed upon enzyme encapsulation, which were dependent on the enzyme concentration and type.

Structure and anisotropic dynamics of stimuli responsive colloidal ellipsoids at the nearest neighbor length scale.

Stimuli-responsive self-assembly of (an) isotropic colloids has resulted in a plethora of self-assembled structures with potential applications in fabricating smart materials. A lack of detailed understanding of the interplay between these self-assembled structures and the resulting dynamics has often impeded the exploitation of their full potential. Herein, we have unveiled the relationship between the field-driven self-assembled structures and the corresponding collective dynamics at the nearest neighbor length scale using X-ray photon correlation spectroscopy and magnetic colloidal ellipsoids.

Counterintuitive Electrostatics upon Metal Ion Coordination to a Receptor with Two Homotopic Binding Sites.

The consecutive binding of two potassium ions to a bis(18-crown-6) analogue of Tröger's base (BCETB) in water was studied by isothermal titration calorimetry using four different salts, KCl, KI, KSCN, and KSO. A counterintuitive result was observed: the enthalpy change associated with the binding of the second ion is more negative than that of the first (Δ < Δ). This remarkable finding is supported by continuum electrostatic theory as well as by atomic scale replica exchange molecular dynamics simulations, where the latter robustly reproduces experimental trends for all simulated salts, KCl, KI, and KSCN, using multiple force fields.

Shape Matters in Magnetic-Field-Assisted Assembly of Prolate Colloids.

An anisotropic colloidal shape in combination with an externally tunable interaction potential results in a plethora of self-assembled structures with potential applications toward the fabrication of smart materials. Here we present our investigation on the influence of an external magnetic field on the self-assembly of hematite-silica core-shell prolate colloids for two aspect ratios ρ = 2.9 and 3.

Analyses of the complex formation of staphylococcal enterotoxin A and the human gp130 cytokine receptor.

Superantigens (SAgs) are bacterial enterotoxins produced by Staphylococcus aureus. Staphylococcal enterotoxin type A (SEA), a staphylococcal superantigen, has been shown to bind to the cytokine signalling receptor glycoprotein 130 (gp130). The structural details, as well as the exact physiological role of this interaction, remain unclear.

Innovative Green Way to Design Biobased Electrospun Fibers from Wheat Gluten and These Fibers' Potential as Absorbents of Biofluids.

In this study, a new method was developed to successfully design sustainable microfibers from wheat gluten proteins using a nonreducing solvent and electrospinning. We explored the morphology by X-ray tomography, scanning electron microscopy (SEM), and confocal laser scanning microscopy (CLSM), protein chemistry and cross-linking by size exclusion-high-performance liquid chromatography (SE-HPLC), and secondary structure by Fourier transform infrared spectroscopy (FT-IR) of fibers containing 15 and 20% of gluten. The impact of heat (130 °C) post-treatment on the polymerization properties of fibers and their absorption performance in different biofluids were also evaluated.