Search results for "FRET"
showing 10 items of 41 documents
Determination of a conformational change in filamin A with Förster resonance energy transfer
2011
Filamins are large rod-like proteins that cross-link actin filaments into three-dimensional networks. They also bind to a plethora of proteins with distinct functions showing that they have a versatile role in cells. Functional filamins are dimers consisting of an N-terminal actin binding domain followed by 24 immunoglobulin-like domains. The most C-terminal domains mediate the dimerization. Two hinge regions are located between the domains 15 and 16 and 23 and 24, respectively, and produce structural flexibility that is essential for the protein function. The domains 18-19 and 20-21 are folded in a pairwise manner in which the first β strands of the even numbered domains are folded along w…
FRET sistēmas aprobācija CRAC jonu kanālu pētījumiem
2016
Fluorescentās rezonanses enerģijas pārneses metodei ir plašs pielietojums mūsdienu zinātnē proteīnu mijiedarbības un konformācijas maiņas petījumos. Tā kā Latvijā pētniecības metode nav izmantota, nepieciešama pilnīga instrumentu, ietekmējošo faktoru un parametru apguve no pašiem pamatiem. Bakalaura darbā “FRET sistēmas aprobācija CRAC jonu kanālu pētījumiem” veikti trīs galvenie eksperimenti, izmantotojot STIM1 ar CFP fluorescento proteīnu C vai N galā molekulas mijiedarbība ar ORAI1, kam N galā YFP proteīns, kuru gaitā uzlabota šūnu audzēšanas tehnika, FRET mikroskopa konfigurācija, kvalitatīvu attēlu uzņemšana un kvalitatīva datu apstrāde. Iegūtas tehniskas prasmes un zināšanas augstas p…
Déréglementation, sécurité et prévision d’accidents extrêmes : le cas du fret ferroviaire français
2010
The deregulation of rail freight has been considered, for long time, as a factor of safety reduction. This article aims to show that, for the moment, one cannot consider that deregulation of rail freight has a significant negative impact on safety in France. Following KJELLÉN (2000), we looked if it's possible to know the periodicity of extreme accidents in this sector.
Biophysical Characterization of Polysialic Acid—Membrane Nanosystems
2019
Polysialic acid (polySia) is a long, membrane-bound, polyanionic polymer (with the degree of polymerization, DP, up to 400) of negatively charged sialic acid monomers. Biological roles of polySia are based on its ability to modulate repulsive and attractive interactions, and its ability to modulate membrane surface charge density, pH at the membrane surface, and membrane potentials. PolySia is used in anti-bacterial and anti-cancer therapies, and in neural tissue repair. Hydrophobically-modified polySia chains can form nano-structures (micelles or liposomes) with high stability and low toxicity for drug delivery. The analysis, based on the Goldman-Hodgkin-Katz equation, of transmembrane pot…
Study and evaluation of fretting critical slip conditions by applying the design of experiments method
2006
Tribological systems are complex systems that require a multi-disciplinary (mechanical, material, physico-chemical) approach where numerous influence factors can be involved. To characterize a contact couple, the intrinsic parameters of the materials as well as the parameters related to the contact loading and the surrounding environment need to be taken into account. Fretting analysis, by means of running condition-fretting maps (RCFM), allows the behavior of the contact couple to be taken into account and to predict the boundary between partial slip and gross slip conditions. This article presents the study of a steel/polycarbonate couple during fretting tests. The study was carried out b…
Microstructural and tribological study of Nd:YAG laser treated titanium plates.
2008
Abstract In this work, the fretting behaviour of pure Ti plates laser treated with a Nd:YAG pulsed laser was compared to that of untreated Ti plates. Fretting tests were done at room temperature without lubrication. The contact geometry was a cylinder (bearing steel) on a plane. The evolution of both the ratio, μ = Q / P , between the normal and the tangential forces, and the Fouvry's energy criterion ( A ) were recorded as a function of the number of fretting cycles, N . Energy dispersive spectrometry and micro-Raman spectroscopy were used to analyse the fretting scars. The oxidized layer formed by the laser treatment displayed a mixed slip regime as a function of N , and a smaller frettin…
Influence of the composition of titanium oxynitride layers on the fretting behavior of functionalized titanium substrates: PVD films versus surface l…
2014
International audience; Abstract In this work we compared the fretting behavior of pure titanium plates functionalized with titanium oxynitride surface layers, obtained by two methods: a Physical Vapor Deposition (PVD) method, reactive magnetron sputtering, and Surface Laser Treatments (SLT), under different mixtures of oxygen and nitrogen. The composition of the layers was determined by nuclear reaction analysis (NRA) and their structure was analyzed by Raman spectroscopy. PVD layers were TiN-like fcc layers, with an oxygen concentration going from 36 to 50 at.%. Three SLT layers were studied. The first one was a TiN-like layer containing ~28 at.% of oxygen. The second one was formed of di…
Single-Molecule FRET Reveals a Cooperative Effect of Two Methyl Group Modifications in the Folding of Human Mitochondrial tRNALys
2011
Summary Using a combination of advanced RNA synthesis techniques and single molecule spectroscopy, the deconvolution of individual contributions of posttranscriptional modifications to the overall folding and stabilization of human mitochondrial tRNA Lys is described. An unexpected destabilizing effect of two pseudouridines on the native tRNA folding was evidenced. Furthermore, the presence of m 2 G10 alone does not facilitate the folding of tRNA Lys , but a stabilization of the biologically functional cloverleaf shape in conjunction with the principal stabilizing component m 1 A9 exceeds the contribution of m 1 A alone. This constitutes an unprecedented cooperative effect of two nucleotide…
Inside a Shell—Organometallic Catalysis Inside Encapsulin Nanoreactors
2021
Abstract Compartmentalization of chemical reactions inside cells are a fundamental requirement for life. Encapsulins are self‐assembling protein‐based nanocompartments from the prokaryotic repertoire that present a highly attractive platform for intracellular compartmentalization of chemical reactions by design. Using single‐molecule Förster resonance energy transfer and 3D‐MINFLUX analysis, we analyze fluorescently labeled encapsulins on a single‐molecule basis. Furthermore, by equipping these capsules with a synthetic ruthenium catalyst via covalent attachment to a non‐native host protein, we are able to perform in vitro catalysis and go on to show that engineered encapsulins can be used …
The membrane environment modulates self-association of the human GpA TM domain--implications for membrane protein folding and transmembrane signaling.
2010
Abstract The influence of lipid bilayer properties on a defined and sequence-specific transmembrane helix–helix interaction is not well characterized yet. To study the potential impact of changing bilayer properties on a sequence-specific transmembrane helix–helix interaction, we have traced the association of fluorescent-labeled glycophorin A transmembrane peptides by fluorescence spectroscopy in model membranes with varying lipid compositions. The observed changes of the glycophorin A dimerization propensities in different lipid bilayers suggest that the lipid bilayer thickness severely influences the monomer–dimer equilibrium of this transmembrane domain, and dimerization was most effici…