To show that DNA containing sharp sequence-directed curvature can preferentially establish ends of supertwisted domains, a highly curved DNA from Crithidia fasciculata was cloned into two sites separated by 28% in pBR325. When this construct (pJGC2) was examined by electron microscopy, 63% of the supercoiled molecules were branched with three or more arms, and the remaining molecules appeared as linear interwound rods. The distance between the tips of two of the arms for the branched molecules measured within 2% of 28% of the DNA contour for 32% of the pJGC2 molecules, as contrasted with only 6.6% for the poorly branched pBR325 DNA. When one of the curved segments in pJGC2 was replaced by a highly curved fragment from SV40, similar results were obtained.
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http://dx.doi.org/10.1016/0092-8674(88)90467-9 | DOI Listing |
Unlabelled: Cytoplasmic proteins must recruit to membranes to function in processes such as endocytosis and cell division. Many of these proteins recognize not only the chemical structure of the membrane lipids, but the curvature of the surface, binding more strongly to more highly curved surfaces, or 'curvature sensing'. Curvature sensing by amphipathic helices is known to vary with membrane bending rigidity, but changes to lipid composition can simultaneously alter membrane thickness, spontaneous curvature, and leaflet symmetry, thus far preventing a systematic characterization of lipid composition on such curvature sensing through either experiment or simulation.
View Article and Find Full Text PDFComput Biol Med
December 2024
Department of Applied Mechanics and Biomedical Engineering, Indian Institute of Technology Madras, Chennai, 600036, Tamil Nadu, India. Electronic address:
Background And Objective: Cerebral aneurysms occur as balloon-like outpouchings in an artery, which commonly develop at the weak curved regions and bifurcations. When aneurysms are detected, understanding the risk of rupture is of immense clinical value for better patient management. Towards this, Fluid-Structure Interaction (FSI) studies can improve our understanding of the mechanics behind aneurysm initiation, progression, and rupture.
View Article and Find Full Text PDFPhys Chem Chem Phys
December 2024
School of Chemistry and Chemical Engineering, Yangzhou University, Yangzhou, Jiangsu 225002, China.
Carboncones and fullerenes are exemplary π-conjugated carbon nanomaterials with unsaturated, positively curved surfaces, enabling the attachment of atoms or functional groups to enhance their physicochemical properties. However, predicting and understanding the addition patterns in functionalized carboncones and fullerenes are extremely challenging due to the formidable complexity of the regioselectivity exhibited in the adducts. Existing predictive models fall short in systems where the carbon molecular framework undergoes severe distortion upon high degrees of addition.
View Article and Find Full Text PDFAngew Chem Int Ed Engl
December 2024
Ecole Normale Supérieure, Department of Chemistry, 24, rue Lhomond, 75005, Paris, FRANCE.
Giant unilamellar vesicles (GUVs) are widely used minimal cell models where essential biological features can be reproduced, isolated and studied. Although precise spatio-temporal distribution of membrane domains is a process of crucial importance in living cells, it is still highly challenging to generate anisotropic GUVs with domains at user-defined positions. Here we describe a novel and robust method to control the spatial position of lipid domains of liquid-ordered (Lo) / liquid-disordered (Ld) phase in giant unilamellar vesicles (GUVs).
View Article and Find Full Text PDFJ Anat
December 2024
Comparative Medicine Lab, Department of Clinical Medicine, Aarhus University, Aarhus, Denmark.
The evolutionary conservation of the building plan of the heart suggests this organ is under substantial form-function constraints. Its form varies to such a degree, however, that it questions whether we understand the form-function relations of the heart. A previously published image of the heart of the sunfish (Mola mola, Tetraodontiformes) indicates the presence of an exceptionally simple topology of the chambers.
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