Academic literature on the topic 'Type IV filament'

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Journal articles on the topic "Type IV filament"

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Braun, Tatjana, Matthijn R. Vos, Nir Kalisman, Nicholas E. Sherman, Reinhard Rachel, Reinhard Wirth, Gunnar F. Schröder, and Edward H. Egelman. "Archaeal flagellin combines a bacterial type IV pilin domain with an Ig-like domain." Proceedings of the National Academy of Sciences 113, no. 37 (August 30, 2016): 10352–57. http://dx.doi.org/10.1073/pnas.1607756113.

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The bacterial flagellar apparatus, which involves ∼40 different proteins, has been a model system for understanding motility and chemotaxis. The bacterial flagellar filament, largely composed of a single protein, flagellin, has been a model for understanding protein assembly. This system has no homology to the eukaryotic flagellum, in which the filament alone, composed of a microtubule-based axoneme, contains more than 400 different proteins. The archaeal flagellar system is simpler still, in some cases having ∼13 different proteins with a single flagellar filament protein. The archaeal flagellar system has no homology to the bacterial one and must have arisen by convergent evolution. However, it has been understood that the N-terminal domain of the archaeal flagellin is a homolog of the N-terminal domain of bacterial type IV pilin, showing once again how proteins can be repurposed in evolution for different functions. Using cryo-EM, we have been able to generate a nearly complete atomic model for a flagellar-like filament of the archaeon Ignicoccus hospitalis from a reconstruction at ∼4-Å resolution. We can now show that the archaeal flagellar filament contains a β-sandwich, previously seen in the FlaF protein that forms the anchor for the archaeal flagellar filament. In contrast to the bacterial flagellar filament, where the outer globular domains make no contact with each other and are not necessary for either assembly or motility, the archaeal flagellin outer domains make extensive contacts with each other that largely determine the interesting mechanical properties of these filaments, allowing these filaments to flex.
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Goosens, Vivianne J., Andreas Busch, Michaella Georgiadou, Marta Castagnini, Katrina T. Forest, Gabriel Waksman, and Vladimir Pelicic. "Reconstitution of a minimal machinery capable of assembling periplasmic type IV pili." Proceedings of the National Academy of Sciences 114, no. 25 (June 6, 2017): E4978—E4986. http://dx.doi.org/10.1073/pnas.1618539114.

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Type IV pili (Tfp), which are key virulence factors in many bacterial pathogens, define a large group of multipurpose filamentous nanomachines widespread in Bacteria and Archaea. Tfp biogenesis is a complex multistep process, which relies on macromolecular assemblies composed of 15 conserved proteins in model gram-negative species. To improve our limited understanding of the molecular mechanisms of filament assembly, we have used a synthetic biology approach to reconstitute, in a nonnative heterologous host, a minimal machinery capable of building Tfp. Here we show that eight synthetic genes are sufficient to promote filament assembly and that the corresponding proteins form a macromolecular complex at the cytoplasmic membrane, which we have purified and characterized biochemically. Our results contribute to a better mechanistic understanding of the assembly of remarkable dynamic filaments nearly ubiquitous in prokaryotes.
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Ching, GY, and RK Liem. "Assembly of type IV neuronal intermediate filaments in nonneuronal cells in the absence of preexisting cytoplasmic intermediate filaments." Journal of Cell Biology 122, no. 6 (September 15, 1993): 1323–35. http://dx.doi.org/10.1083/jcb.122.6.1323.

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We report here on the in vivo assembly of alpha-internexin, a type IV neuronal intermediate filament protein, in transfected cultured cells, comparing its assembly properties with those of the neurofilament triplet proteins (NF-L, NF-M, and NF-H). Like the neurofilament triplet proteins, alpha-internexin coassembles with vimentin into filaments. To study the assembly characteristics of these proteins in the absence of a preexisting filament network, transient transfection experiments were performed with a non-neuronal cell line lacking cytoplasmic intermediate filaments. The results showed that only alpha-internexin was able to self-assemble into extensive filamentous networks. In contrast, the neurofilament triplet proteins were incapable of homopolymeric assembly into filamentous arrays in vivo. NF-L coassembled with either NF-M or NF-H into filamentous structures in the transfected cells, but NF-M could not form filaments with NF-H. alpha-internexin could coassemble with each of the neurofilament triplet proteins in the transfected cells to form filaments. When all but 2 and 10 amino acid residues were removed from the tail domains of NF-L and NF-M, respectively, the resulting NF-L and NF-M deletion mutants retained the ability to coassemble with alpha-internexin into filamentous networks. These mutants were also capable of forming filaments with other wild-type neurofilament triplet protein subunits. These results suggest that the tail domains of NF-L and NF-M are dispensable for normal coassembly of each of these proteins with other type IV intermediate filament proteins to form filaments.
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Ching, G. Y., and R. K. Liem. "Analysis of the roles of the head domains of type IV rat neuronal intermediate filament proteins in filament assembly using domain-swapped chimeric proteins." Journal of Cell Science 112, no. 13 (July 1, 1999): 2233–40. http://dx.doi.org/10.1242/jcs.112.13.2233.

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Type IV neuronal intermediate filament proteins consist of alpha-internexin, which can self-assemble into filaments and the neurofilament triplet proteins, which are obligate heteropolymers, at least in rodents. These IF proteins therefore provide good systems for elucidating the mechanism of intermediate filament assembly. To analyze the roles of the head domains of these proteins in contributing to their differential assembly properties, we generated chimeric proteins by swapping the head domains between rat alpha-internexin and either rat NF-L or NF-M and examined their assembly properties in transfected cells that lack their own cytoplasmic intermediate filament network. Lalphaalpha and Malphaalpha, the chimeric proteins generated by replacing the head domain of alpha-internexin with those of NF-L and NF-M, respectively, were unable to self-assemble into filaments. In contrast, alphaLL, a chimeric NF-L protein generated by replacing the head domain of NF-L with that of alpha-internexin, was able to self-assemble into filaments, whereas MLL, a chimeric NF-L protein containing the NF-M head domain, was unable to do so. These results demonstrate that the alpha-internexin head domain is essential for alpha-internexin's ability to self-assemble. While coassembly of Lalphaalpha with NF-M and coassembly of Malphaalpha with NF-L resulted in formation of filaments, coassembly of Lalphaalpha with NF-L and coassembly of Malphaalpha with NF-M yielded punctate patterns. These coassembly results show that heteropolymeric filament formation requires that one partner has the NF-L head domain and the other partner has the NF-M head domain. Thus, the head domains of rat NF-L and NF-M play important roles in determining the obligate heteropolymeric nature of filament formation. The data obtained from these self-assembly and coassembly studies provide some new insights into the mechanism of intermediate filament assembly.
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Kraljic, Katarina, Christopher Duckworth, Rita Tojeiro, Shadab Alam, Dmitry Bizyaev, Anne-Marie Weijmans, Nicholas Fraser Boardman, and Richard R. Lane. "SDSS-IV MaNGA: 3D spin alignment of spiral and S0 galaxies." Monthly Notices of the Royal Astronomical Society 504, no. 3 (April 21, 2021): 4626–33. http://dx.doi.org/10.1093/mnras/stab1109.

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ABSTRACT We investigate the 3D spin alignment of galaxies with respect to the large-scale filaments using the MaNGA survey. The cosmic web is reconstructed from the Sloan Digital Sky Survey using disperse and the 3D spins of MaNGA galaxies are estimated using the thin disc approximation with integral field spectroscopy kinematics. Late-type spiral galaxies are found to have their spins parallel to the closest filament’s axis. The alignment signal is found to be dominated by low-mass spirals. Spins of S0-type galaxies tend to be oriented preferentially in perpendicular direction with respect to the filament’s axis. This orthogonal orientation is found to be dominated by S0s that show a notable misalignment between their kinematic components of stellar and ionized gas velocity fields and/or by low-mass S0s with lower rotation support compared to their high-mass counterparts. Qualitatively similar results are obtained when splitting galaxies based on the degree of ordered stellar rotation, such that galaxies with high spin magnitude have their spin aligned, and those with low spin magnitude in perpendicular direction to the filaments. In the context of conditional tidal torque theory, these findings suggest that galaxies’ spins retain memory of their larger scale environment. In agreement with measurements from hydrodynamical cosmological simulations, the measured signal at low redshift is weak, yet statistically significant. The dependence of the spin-filament orientation of galaxies on their stellar mass, morphology, and kinematics highlights the importance of sample selection to detect the signal.
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Couturier, Marc Roger, and Markus Stein. "Helicobacter pylori produces unique filaments upon host contact in vitro." Canadian Journal of Microbiology 54, no. 7 (July 2008): 537–48. http://dx.doi.org/10.1139/w08-042.

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Helicobacter pylori exists in 2 distinct morphological states, helicoid and coccoid. Both have been observed in in vitro culture and in gastric biopsies. We visualized H. pylori during AGS cell infections using immunofluorescence microscopy. Anti-H. pylori mouse serum as well as human serum from H. pylori-positive patients recognized long, thin bacterial filaments, which formed on helicoids and more frequently on coccoids. These filaments reached lengths of 59 μm and often connected bacteria. Periodate oxidation abolished antibody recognition, suggesting that carbohydrates compose a major antigenic component of the filaments. Similar to results obtained using immunofluorescence microscopy, scanning electron microscopy imaging revealed thin filamentous structures, which were absent on uninfected cells. Both coccoid conversion and filament development increased over the time course of infection with peak filament formation at 4 h. The number of visible filaments then decreased as bacteria clustered on the apical surface of AGS cells. Since the observed filaments were clearly distinct from previously described surface structures, including flagella and the cag type IV secretion system, our results demonstrate that these filaments represent a unique, previously unrecognized, organelle.
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Sheppard, Devon, Jamie-Lee Berry, Rémi Denise, Eduardo P. C. Rocha, Steve Matthews, and Vladimir Pelicic. "The major subunit of widespread competence pili exhibits a novel and conserved type IV pilin fold." Journal of Biological Chemistry 295, no. 19 (April 9, 2020): 6594–604. http://dx.doi.org/10.1074/jbc.ra120.013316.

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Type IV filaments (T4F), which are helical assemblies of type IV pilins, constitute a superfamily of filamentous nanomachines virtually ubiquitous in prokaryotes that mediate a wide variety of functions. The competence (Com) pilus is a widespread T4F, mediating DNA uptake (the first step in natural transformation) in bacteria with one membrane (monoderms), an important mechanism of horizontal gene transfer. Here, we report the results of genomic, phylogenetic, and structural analyses of ComGC, the major pilin subunit of Com pili. By performing a global comparative analysis, we show that Com pili genes are virtually ubiquitous in Bacilli, a major monoderm class of Firmicutes. This also revealed that ComGC displays extensive sequence conservation, defining a monophyletic group among type IV pilins. We further report ComGC solution structures from two naturally competent human pathogens, Streptococcus sanguinis (ComGCSS) and Streptococcus pneumoniae (ComGCSP), revealing that this pilin displays extensive structural conservation. Strikingly, ComGCSS and ComGCSP exhibit a novel type IV pilin fold that is purely helical. Results from homology modeling analyses suggest that the unusual structure of ComGC is compatible with helical filament assembly. Because ComGC displays such a widespread distribution, these results have implications for hundreds of monoderm species.
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Daehnel, Katrin, Robin Harris, Lucinda Maddera, and Philip Silverman. "Fluorescence assays for F-pili and their application." Microbiology 151, no. 11 (November 1, 2005): 3541–48. http://dx.doi.org/10.1099/mic.0.28159-0.

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Conjugative pili are extracellular filaments elaborated by Gram-negative bacteria expressing certain type IV secretion systems. They are required at the earliest stages of conjugal DNA transfer to establish specific and secure cell–cell contacts. Conjugative pili also serve as adsorption organelles for both RNA and DNA bacteriophages. Beyond these facts, the structure, formation and function of these filaments are poorly understood. This paper describes a rapid, quantitative assay for F-pili encoded by the F plasmid type IV secretion system. The assay is based on the specific lateral adsorption of icosahedral RNA bacteriophage R17 by F-pili. Bacteriophage particles conjugated with a fluorescent dye, Alexa 488, and bound to F-pili defined filaments visible by immunofluorescence microscopy. F-pili attached to F+ cells and free F-pili were both visible by this method. For quantification, cell-bound bacteriophage were separated from free bacteriophage particles by sedimentation and released by suspending cell pellets in 0·1 % SDS. Fluorescence in cell-free supernatant fractions was measured by fluorometry. The authors present a characterization of this assay and its application to F-pilus formation by cells carrying mutations in the gene for the F-pilus subunit F-pilin. Each mutation introduced a cysteine, which F-pilin normally lacks, at a different position in its primary structure. Cysteine residues in the N-terminal domain I abolished filament formation as measured by fluorescent R17 binding. This was confirmed by measurements of DNA donor activity and filamentous DNA bacteriophage infection. With one exception (G53C), cysteines elsewhere in the F-pilin primary structure did not abolish filament formation, although some mutations differentially affected F-pilus functions.
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Uddin, Wahab, and V. K. Verma. "Eruption of a Twisted Filament and Associated Phenomena." International Astronomical Union Colloquium 167 (1998): 338–41. http://dx.doi.org/10.1017/s0252921100047874.

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AbstractIn this paper we present CCD observations between February 14–20, 1994 and analysis of the giant twisted filament evolved in the active region NOAA 7671. The dynamic eruption of the filament was accompanied by a major flare (3B/M4), CME, long duration type II, IV radio bursts, great microwave bursts, a long duration soft X-ray burst, SIDs, strong geomagnetic storms and a very energetic proton flare. We analysed and estimated the twist, length, volume, mass and energy associated with filament system between February 14 and 20, 1994. The present study shows that the magnetic energy required for the solar flare came from the filament system associated with the solar flare and associated phenomena.
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Wang, Qiang, Genrich V. Tolstonog, Robert Shoeman, and Peter Traub. "Sites of Nucleic Acid Binding in Type I−IV Intermediate Filament Subunit Proteins†." Biochemistry 40, no. 34 (August 2001): 10342–49. http://dx.doi.org/10.1021/bi0108305.

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Dissertations / Theses on the topic "Type IV filament"

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Leh, David. "Optimisation du dimensionnement d'un réservoir composite type IV pour stockage très haute pression d'hydrogène." Phd thesis, Université de Grenoble, 2013. http://tel.archives-ouvertes.fr/tel-00942731.

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Ce travail a pour but de proposer une nouvelle approche du dimensionnement optimisé des réservoirs de stockage d'hydrogène de type IV visant à mieux répondre aux enjeux industriels. Les objectifs scientifiques et techniques consistent à disposer de modèles qualifiés pour la simulation du comportement de ces réservoirs, associés à des méthodologies de dimensionnement et d'optimisation fiables. La démarche s'appuie sur trois axes principaux :- proposer une démarche de conception prédictive en intégrant (i) un premier aspect lié à la ruine de la structure qui est la conséquence de mécanismes complexes et multiples d'endommagement s'initiant, s'accumulant et se développant dans un milieu anisotrope et (ii) des modèles de simulation de la structuration composite spécifique au procédé d'enroulement filamentaire, technologie employée largement dans la fabrication des réservoirs de stockage à haute pression. Leurs implémentations constituent une première avancée face à l'existant ;- choisir et évaluer les paramètres structuraux par une démarche d'optimisation où nous sommes amenés à utiliser (i) des méthodes de métamodélisation permettant de répondre aux contraintes de coûts, (ii) des méthodes spécifiques de tri et (iii) des méthodes à spectres larges qui recherchent des solutions sur une large population telles que des méthodes génétiques ;- qualifier la démarche dans sa globalité par une comparaison entre calculs et essais. Ainsi, la finalité de ce travail est de développer et valider des modèles et méthodes pour permettre de mieux concevoir, tester et fabriquer à moindre coût un réservoir avec une structure calculée optimisée.
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Conference papers on the topic "Type IV filament"

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Farhood, Naseer H., Saravanan Karuppanan, H. H. Ya, and Mohamad Ariff Baharom. "Burst pressure investigation of filament wound type IV composite pressure vessel." In ADVANCED MATERIALS FOR SUSTAINABILITY AND GROWTH: Proceedings of the 3rd Advanced Materials Conference 2016 (3rd AMC 2016). Author(s), 2017. http://dx.doi.org/10.1063/1.5010482.

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