The European Air Transport Command (EATC) is a seven-nation integrated command. One of its core capabilities is strategic aeromedical evacuation (AE). During the global COVID-19 pandemic and Ukrainian crisis, EATC proved that acting in concert is a valuable, effective, and reliable option.
View Article and Find Full Text PDFSpectrochim Acta A Mol Biomol Spectrosc
February 2024
The recently developed photoinduced force microscopy for mid-infrared (PiF-IR) offers high spectral resolution in combination with surface sensitivity and a spatial resolution in the range of a few nanometers. Although PiF-IR has primarily been applied to polymer materials, this technology presents significant potential for the chemical characterization of cellular structures approaching single-molecule sensitivity. We applied PiF-IR to differently polymerized F-Actin samples finding general agreement with FTIR spectra from the same samples.
View Article and Find Full Text PDFDrift-diffusion dynamics is investigated in a one-dimensional (1D) exciton guide at room temperature. Spatial engineering of the exciton energy in a WSe monolayer is achieved using local strain to confine and direct exciton transport. An unexpected and massive deviation from the Einstein relation is observed and correlated to exciton capture by defects.
View Article and Find Full Text PDFFF-ATP synthases in mitochondria, in chloroplasts, and in most bacteria are proton-driven membrane enzymes that supply the cells with ATP made from ADP and phosphate. Different control mechanisms exist to monitor and prevent the enzymes' reverse chemical reaction of fast wasteful ATP hydrolysis, including mechanical or redox-based blockade of catalysis and ADP inhibition. In general, product inhibition is expected to slow down the mean catalytic turnover.
View Article and Find Full Text PDFDelocalized Bloch electrons and the low-energy correlations between them determine key optical, electronic and entanglement functionalities of solids, all the way through to phase transitions. To directly capture how many-body correlations affect the actual motion of Bloch electrons, subfemtosecond (1 fs = 10 s) temporal precision is desirable. Yet, probing with attosecond (1 as = 10 s) high-energy photons has not been energy-selective enough to resolve the relevant millielectronvolt-scale interactions of electrons near the Fermi energy.
View Article and Find Full Text PDFFF-ATP synthases are ubiquitous membrane-bound, rotary motor enzymes that can catalyze ATP synthesis and hydrolysis. Their enzyme kinetics are controlled by internal subunit rotation, by substrate and product concentrations, and by mechanical inhibitory mechanisms but also by the electrochemical potential of protons across the membrane. Single-molecule Förster resonance energy transfer (smFRET) has been used to detect subunit rotation within FF-ATP synthases embedded in freely diffusing liposomes.
View Article and Find Full Text PDFExternally controlled microswimmers offer prospects for transport in biological research and medical applications. This requires biocompatibility of the swimmers and the possibility to tailor their propulsion mechanisms to the respective low Reynolds number environment. Here, we incorporate low amounts of the biocompatible alloy of iron and platinum (FePt) in its [Formula: see text] phase in microstructures by a versatile one-step physical vapor deposition process.
View Article and Find Full Text PDFSearching for quantum functionalities requires access to the electronic structure, constituting the foundation of exquisite spin-valley-electronic, topological, and many-body effects. All-optical band-structure reconstruction could directly connect electronic structure with the coveted quantum phenomena if strong lightwaves transported localized electrons within preselected bands. Here, we demonstrate that harmonic sideband (HSB) generation in monolayer tungsten diselenide creates distinct electronic interference combs in momentum space.
View Article and Find Full Text PDFLight-driven ATP regeneration systems combining ATP synthase and bacteriorhodopsin have been proposed as an energy supply in the field of synthetic biology. Energy is required to power biochemical reactions within artificially created reaction compartments like protocells, which are typically based on either lipid or polymer membranes. The insertion of membrane proteins into different hybrid membranes is delicate, and studies comparing these systems with liposomes are needed.
View Article and Find Full Text PDFF-ATP synthases use proton flow through the F domain to synthesize ATP in the F₁ domain. In , the enzyme consists of rotor subunits γε and stator subunits (αβ)₃δ₂. Subunits or (αβ)₃ alone are rotationally symmetric.
View Article and Find Full Text PDFSingle-pair Förster resonance energy transfer (spFRET) has become an important tool for investigating conformational dynamics in biological systems. To extract dynamic information from the spFRET traces measured with total internal reflection fluorescence microscopy, we extended the hidden Markov model (HMM) approach. In our extended HMM analysis, we incorporated the photon-shot noise from camera-based systems into the HMM.
View Article and Find Full Text PDFSelf-propelled chemical motors are chemically powered micro- or nanosized swimmers. The energy required for these motors' active motion derives from catalytic chemical reactions and the transformation of a fuel dissolved in the solution. While self-propulsion is now well established for larger particles, it is still unclear if enzymes, nature's nanometer-sized catalysts, are potentially also self-powered nanomotors.
View Article and Find Full Text PDFTargeting the mitochondrial enzyme FF-ATP synthase and modulating its catalytic activities with small molecules is a promising new approach for treatment of autoimmune diseases. The immunomodulatory compound Bz-423 is such a drug that binds to subunit OSCP of the mitochondrial FF-ATP synthase and induces apoptosis increased reactive oxygen production in coupled, actively respiring mitochondria. Here, we review the experimental progress to reveal the binding of Bz-423 to the mitochondrial target and discuss how subunit rotation of FF-ATP synthase is affected by Bz-423.
View Article and Find Full Text PDFProc SPIE Int Soc Opt Eng
February 2018
Neurotensin receptor 1 (NTSR1) is a G protein-coupled receptor that is important for signaling in the brain and the gut. Its agonist ligand neurotensin (NTS), a 13-amino-acid peptide, binds with nanomolar affinity from the extracellular side to NTSR1 and induces conformational changes that trigger intracellular signaling processes. Our goal is to monitor the conformational dynamics of single fluorescently labeled NTSR1.
View Article and Find Full Text PDFBiochim Biophys Acta Bioenerg
September 2018
F-type ATP synthases are extraordinary multisubunit proteins that operate as nanomotors. The Escherichia coli (E. coli) enzyme uses the proton motive force (pmf) across the bacterial plasma membrane to drive rotation of the central rotor subunits within a stator subunit complex.
View Article and Find Full Text PDFThe allosteric interplay between distant functional sites present in a single protein provides for one of the most important regulatory mechanisms in biological systems. While the design of ligand-binding sites into proteins remains challenging, this holds even truer for the coupling of a newly engineered binding site to an allosteric mechanism that regulates the ligand affinity. Here it is shown how computational design algorithms enabled the introduction of doxycycline- and doxorubicin-binding sites into the serine proteinase inhibitor (serpin) family member α1-antichymotrypsin.
View Article and Find Full Text PDFCompartments for the spatially and temporally controlled assembly of biological processes are essential towards cellular life. Synthetic mimics of cellular compartments based on lipid-based protocells lack the mechanical and chemical stability to allow their manipulation into a complex and fully functional synthetic cell. Here, we present a high-throughput microfluidic method to generate stable, defined sized liposomes termed 'droplet-stabilized giant unilamellar vesicles (dsGUVs)'.
View Article and Find Full Text PDFIn archaea the A A ATP synthase uses a transmembrane electrochemical potential to generate ATP, while the soluble A domain (subunits A B DF) alone can hydrolyse ATP. The three nucleotide-binding AB pairs form a barrel-like structure with a central orifice that hosts the rotating central stalk subunits DF. ATP binding, hydrolysis and product release cause a conformational change inside the A:B-interface, which enforces the rotation of subunits DF.
View Article and Find Full Text PDFIntroduction: Whilst initial closed reduction followed by definitive open fixation is widely applied in the treatment of distal radial fractures, the effect of the closed reduction on the reconstruction of the articular surface remains unclear. Our research questions were:
Methods: Palmar tilt and radiocarpal inclination of 425 patients were measured at admission, following initial closed reduction and after surgical reconstruction.
Results: Closed reduction increased palmar tilt by 12.
Proc SPIE Int Soc Opt Eng
April 2014
F-ATPase is the soluble portion of the membrane-embedded enzyme FF-ATP synthase that catalyzes the production of adenosine triphosphate in eukaryotic and eubacterial cells. In reverse, the F part can also hydrolyze ATP quickly at three catalytic binding sites. Therefore, catalysis of 'non-productive' ATP hydrolysis by F (or FF) must be minimized in the cell.
View Article and Find Full Text PDFProc SPIE Int Soc Opt Eng
February 2014
Subunit ε is an intrinsic regulator of the bacterial FF-ATP synthase, the ubiquitous membrane-embedded enzyme that utilizes a proton motive force in most organisms to synthesize adenosine triphosphate (ATP). The C-terminal domain of ε can extend into the central cavity formed by the α and β subunits, as revealed by the recent X-ray structure of the F portion of the enzyme. This insertion blocks the rotation of the central γ subunit and, thereby, prevents wasteful ATP hydrolysis.
View Article and Find Full Text PDFSubunit rotation is the mechanochemical intermediate for the catalytic activity of the membrane enzyme FoF1-ATP synthase. smFRET (single-molecule FRET) studies have provided insights into the step sizes of the F1 and Fo motors, internal transient elastic energy storage and controls of the motors. To develop and interpret smFRET experiments, atomic structural information is required.
View Article and Find Full Text PDFSingle-molecule Förster resonance energy (smFRET) transfer has become a powerful tool for observing conformational dynamics of biological macromolecules. Analyzing smFRET time trajectories allows to identify the state transitions occuring on reaction pathways of molecular machines. Previously, we have developed a smFRET approach to monitor movements of the two nucleotide binding domains (NBDs) of P-glycoprotein (Pgp) during ATP hydrolysis driven drug transport in solution.
View Article and Find Full Text PDFMembrane protein translocation and insertion is a central issue in biology. Here we focus on a minimal system, the membrane insertase YidC of Escherichia coli that inserts small proteins into the cytoplasmic membrane. In a reconstituted system individual insertion processes were followed by single-pair fluorescence resonance energy transfer (FRET), with a pair of fluorophores on YidC and the substrate Pf3 coat protein.
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