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Nanomedicine Against COVID-19
Published in Hanadi Talal Ahmedah, Muhammad Riaz, Sagheer Ahmed, Marius Alexandru Moga, The Covid-19 Pandemic, 2023
Saima Zulfiqar, Zunaira Naeem, Shahzad Sharif, Ayoub Rashid Ch., M. Zia-Ul-Haq, Marius Moga
Covering of Qß capsids with envelop of A/X31 virus and minimizing the interaction with host cell has been demonstrated by cryoelectron tomography in Figure 12.19. Inactivation of virus by nanoparticles present in phage capsid is being investigated by in vitro, in vivo, and ex vivo analysis.
Pathogenesis
Published in Marie Studahl, Paola Cinque, Tomas Bergström, Herpes Simplex Viruses, 2017
HSV-1 is a typical herpes virus consisting of a double-stranded DNA constituting of an electron-dense core within the icosahedral nucleocapsid built up by 162 capsomers. The nucleocapsid is surrounded by the adherent tegument, which in turn is tightly connected to the envelope. The structure of the enveloped particle was recently resolved by cryo-electron tomography (Fig. 1), where the tegument appeared to be asymmetric due to eccentric positioning of the nucleocapsid and displayed a partly filamentous, actin-like structure (1). Moreover, protruding envelope glycoproteins are of several morphological types, and these spikes tended to be nonrandomly clustered, which could be of possible functional importance during viral entry. Although HSV-2 virions seem to be more fragile and therefore less studied, the similarity of viral genes and their organization and expression between the two subtypes (see chap. 1) argues for a similarity in structure also.
Rigid monoclonal antibodies improve detection of SARS-CoV-2 nucleocapsid protein
Published in mAbs, 2021
Curtis D. Hodge, Daniel. J. Rosenberg, Patricia Grob, Mateusz Wilamowski, Andrzej Joachimiak, Greg L. Hura, Michal Hammel
IgG flexibility, its importance in improving mAb recognition, and its influence on agglutination have remained uncharacterized. Although there have been several attempts by cryo-electron tomography25–28 and negative stain (NS) electron tomography,29 large-scale flexibility measurements are often not amenable to single-particle techniques. In contrast, the resolution of small-angle X-ray scattering (SAXS) is sufficient, especially when atomic structures of individual components are available, to determine the conformational variability of the antigen-binding fragments (Fabs) in various antibodies,30 including complexes with antigens or Fc-gamma receptors (FcγRs).31,32 A previous study showed that the Fabs’ conformational flexibility is derived from the inherent plasticity of the Fc-hinge regions in solution.33 Rigidity of the hinges inversely correlates with, and can modulate mAb agonistic potency,34,35 and this highlights the importance of newer strategies to modulate antibody-agglutination.36
Focus on centrin in normal and altered human spermatozoa
Published in Systems Biology in Reproductive Medicine, 2023
Elena Moretti, Daria Noto, Roberta Corsaro, Giulia Collodel
Regarding spermatozoa, Le Guennec et al. (2020) discovered in centrioles of different species an inner scaffold based on centrin 2 involved in centriole cohesion. They employed cryo-electron tomography and subtomogram averaging, a potent technique of image processing in electron tomography that allows determining the three-dimensional structure of the different macromolecular complexes. These sophisticated methods should be applied to normal and pathological human sperm.
The phosphoinositide code is read by a plethora of protein domains
Published in Expert Review of Proteomics, 2021
Michael Overduin, Troy A. Kervin
The development of new tools to visualize and manipulate membrane readers bound to lipids and membranes at atomic resolution has revolutionized our understanding of biology. The recognition mechanisms involve hundreds of electrostatically polarized domains ranging from 50 to 300 residues. They present basic surfaces that bind patches of lipid molecules while inserting hydrophobic groups into bilayers of various fluidities and curvatures. Complementary insights of these multivalent engagements are provided by NMR spectroscopy, X-ray crystallography, cryo-electron microscopy (cEM) and cryo-electron tomography (cET), thus exposing their complex mechanisms as outlined here. The application of computational tools including Membrane Optimal Docking Area (MODA) [21] and HADDOCK [22] allow modeling of protein: membrane complexes, while the trajectories of their multi-component assemblies are becoming accessible by molecular dynamic simulations [23]. Amphipathic polymers such as styrene maleic acid (SMA) enable detergent-free purification analysis of native assemblies of proteins with minimum perturbation of their associated asymmetric lipid bilayer environments [24], and reveal how PIs modulate signaling inside membranes [25]. Cell imaging of fluorescent proteins using PI-specific probes allows the subcellular recruitment of many targets to be monitored. Mutagenesis of PI-binding determinants combined with selective inhibition of PI kinases allows unambiguous determination of cognate PI ligands in cells. Quantitative binding assays including biolayer interferometry, NMR, and isothermal titration calorimetry can cross-validate novel lipid ligands in micelles, bicelles, nanodiscs, and liposomes [26]. These advances are allowing closer examination of how membrane readers engage the organelle-specific lipid combinations in order to mediate localized membrane trafficking, assembly, and signaling events. Our cross-examination of their mechanisms reveals common features. The consensus is that PI code readers stereospecifically recognize a phosphorylated inositol headgroup while simultaneously engaging a few neighboring lipids and inserting hydrophobic elements into the membrane interior, subject to control by covalent modifications of both protein and lipid components.