The yeast DNA-binding protein GCN4 forms a homo-dimer through a self-complementary coiled-coil interface. In this article, we describe how such coiled-coils might be bistable and, through Molecular Dynamics computations on the GCN4 coiled coil, we show that the coiled coil can indeed switch between the two states by a pathway in which there is a progressive "flipping" of consecutive steps along the interface. We discuss the general implications of potentially bistable coiled-coil interfaces for allosteric signal-transmission mechanisms along homo-dimeric coiled coils and for the packing of helices in globular proteins.
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http://dx.doi.org/10.1002/prot.21596 | DOI Listing |
Neuroradiol J
January 2025
Department of Radiology and Radiological Science, Medical University of South Carolina, USA.
We describe a novel application of photon-counting detector CT (PCD-CT) in neurovascular imaging by harnessing the improved spatial resolution, attenuation of electronic noise, and reduction of metal artifacts. The presented case offers the unique challenge of high-quality imaging for the assessment of treated and untreated intracranial saccular aneurysms, in the setting of metal artifacts from embolization coils. Our goal was to explore optimized reconstruction parameters for ultra-high-resolution imaging (UHR) using a dedicated, sharp neurovascular kernel (Hv72) and the highest strength of quantum iterative reconstruction (QIR-4) for detailed characterization of the vasculature.
View Article and Find Full Text PDFSci Transl Med
January 2025
Department of Cell Biology and Physiology, Washington University School of Medicine, Saint Louis, MO 63110, USA.
Langmuir
January 2025
Department of Materials Science and Engineering, University of Delaware, Newark, Delaware 19716, United States.
We synthesized rigid, macromolecular brushes with well-defined and quantized brush lengths on a gold nanoparticle substrate by using a macromolecular "grafting from" approach. The macromonomers used in these brushes were thiol- and maleimide-functionalized peptide coiled coil "bundlemers" that fold into discrete 4 nm × 2 nm (length × diameter) cylindrical nanoparticles. With each added peptide macromonomer layer, brush thickness increased by approximately the length of a single bundlemer nanoparticle.
View Article and Find Full Text PDFMed Phys
January 2025
Institute of Plasma Physics, Hefei Institutes of Physical Science, Chinese Academy of Sciences, Hefei, China.
Background: High-resolution brain imaging is crucial in clinical diagnosis and neuroscience, with ultra-high field strength MRI systems ( ) offering significant advantages for imaging neuronal microstructures. However, achieving magnetic field homogeneity is challenging due to engineering faults during the installation of superconducting strip windings and the primary magnet.
Purpose: This study aims to design and optimize active superconducting shim coils for a 7 T animal MRI system, focusing on the impact of safety margin, size, and adjustability of the second-order shim coils on the MRI system's optimization.
Int J Dev Biol
January 2025
Faculty of Biochemistry and Molecular Medicine, University of Oulu, Finland.
Male infertility is a multifactorial condition for which the underlying causes frequently remain undefined. Genetic factors have long been associated with male fertility. However, many of them are poorly or not at all characterized and their biological functions are unknown.
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