Publications by authors named "A K Meents"
We report on recent developments that enable megahertz hard X-ray phase contrast imaging (MHz XPCI) experiments at the Single Particles, Clusters, and Biomolecules and Serial Femtosecond Crystallography (SPB/SFX) instrument of the European XFEL facility (EuXFEL). We describe the technical implementation of the key components, including an MHz fast camera and a modular indirect X-ray microscope system based on fast scintillators coupled through a high-resolution optical microscope, which enable full-field X-ray microscopy with phase contrast of fast and irreversible phenomena. The image quality for MHz XPCI data showed significant improvement compared with a pilot demonstration of the technique using parallel beam illumination, which also allows access to up to 24 keV photon energies at the SPB/SFX instrument of the EuXFEL.
View Article and Find Full Text PDFCables formed by head-to-tail polymerization of tropomyosin, localized along the length of sarcomeric and cytoskeletal actin filaments, play a key role in regulating a wide range of motile and contractile processes. The stability of tropomyosin cables, their interaction with actin filaments and the functional properties of the resulting co-filaments are thought to be affected by N-terminal acetylation of tropomyosin. Here, we present high-resolution structures of cables formed by acetylated and unacetylated Schizosaccharomyces pombe tropomyosin ortholog Tpm.
View Article and Find Full Text PDFX-ray multi-projection imaging (XMPI) is an emerging experimental technique for the acquisition of rotation-free, time-resolved, volumetric information on stochastic processes. The technique is developed for high-brilliance light-source facilities, aiming to address known limitations of state-of-the-art imaging methods in the acquisition of 4D sample information, linked to their need for sample rotation. XMPI relies on a beam-splitting scheme, that illuminates a sample from multiple, angularly spaced viewpoints, and employs fast, indirect, X-ray imaging detectors for the collection of the data.
View Article and Find Full Text PDFArticle Synopsis
- The main protease (M) of SARS-CoV-2 is crucial for the virus's functionality and is considered a potential target for drug development, as it is only active in its reduced form.
- When oxidized, M's activity halts but can be restored, indicating an evolutionary adaptation to oxidative environments, although the protective mechanisms haven't been fully elucidated.
- Researchers determined the crystal structure of oxidized M, revealing a disulfide bond that affects its dimer stability and crystallization, providing insights into the protein's response to oxidative stress and its structural study conditions.*
Article Synopsis
- Emerging RNA viruses like SARS-CoV-2 pose significant health risks, with the virus entering cells through pathways that rely on cysteine cathepsins, particularly cathepsin L (CatL), a potential target for treatment.
- * Researchers explored a range of inhibitors targeting CatL, finding that compounds such as Calpain inhibitor XII and MG-101 show strong antiviral effects at very low concentrations in specific cell lines.
- * The study also revealed an off-target effect of some inhibitors and provided detailed crystal structures of CatL, which can help in designing better drug candidates against protease-related diseases.