90 research outputs found
Signal transduction in oligoamide foldamers by selective non-covalent binding of chiral phosphates at a urea binding site
Non-covalent interactions between a chiral phosphate anion and a urea binding site induce a conformational preference in an amide foldamer.</p
Conformational analysis of some pyridinium phenolates and synthetic precursors based on X-Ray and IR characterisations
7 pagesInternational audienceThis manuscript reports X-Ray and IR characterizations of representative pyridinium phenolates, model compounds for nonlinear optics. These analyses reveal the close dependence existing between molecular structure and the contribution of quinone and zwitterionic limiting forms. The bond length alternation (BLA) values, the well-known parameter correlated to hyperpolarisability β, are also discussed and compared with literature data
High expression of antioxidant proteins in dendritic cells: possible implications in atherosclerosis
Dendritic cells (DCs) display the unique ability to activate naive T cells
and to initiate primary T cell responses revealed in DC-T cell alloreactions.
DCs frequently operate under stress conditions. Oxidative stress enhances the
production of inflammatory cytokines by DCs. We performed a proteomic analysis
to see which major changes occur, at the protein expression level, during DC
differentiation and maturation. Comparative two-dimensional gel analysis of the
monocyte, immature DC, and mature DC stages was performed. Manganese superoxide
dismutase (Mn-SOD) reached 0.7% of the gel-displayed proteins at the mature DC
stage. This important amount of Mn-SOD is a primary antioxidant defense system
against superoxide radicals, but its product, H(2)O(2), is also deleterious for
cells. Peroxiredoxin (Prx) enzymes play an important role in eliminating such
peroxide. Prx1 expression level continuously increased during DC
differentiation and maturation, whereas Prx6 continuously decreased, and Prx2
peaked at the immature DC stage. As a consequence, DCs were more resistant than
monocytes to apoptosis induced by high amounts of oxidized low density
lipoproteins containing toxic organic peroxides and hydrogen peroxide.
Furthermore DC-stimulated T cells produced high levels of receptor activator of
nuclear factor kappaB ligand, a chemotactic and survival factor for monocytes
and DCs. This study provides insights into the original ability of DCs to
express very high levels of antioxidant enzymes such as Mn-SOD and Prx1, to
detoxify oxidized low density lipoproteins, and to induce high levels of
receptor activator of nuclear factor kappaB ligand by the T cells they activate
and further emphasizes the role that DCs might play in atherosclerosis, a
pathology recognized as a chronic inflammatory disorder.Comment: cpyright: American Society of Biochemistry and Molecular Biolog
El rechazo entre iguales: una visión general
III Jornadas Internacionales del Grupo GREIHablar de aceptación y rechazo entre iguales es un tema de gran relevancia en nuestro contexto social actual. Este hecho es consecuencia de la importancia que tiene la atracción interpersonal como índice de adaptación socioemocional, ya que la realidad evidencia que una buena aceptación en el grupo de compañeros y compañeras favorece una buena adaptación y bienestar socioemocional, mientras que niveles bajos de aceptación social son factores de riesgo y de problemática en el tema de interacción socialAcceptance and rejection between peers have become a relevant issue in our
current social context. This is a consequence of the importance that interpersonal
attraction is bestowed as a socio-emotional adaptation system. Indeed, as reality
evidences, strong acceptance levels among peers foster not only better adaptation
within the group but also better levels of socio-emotional well-being. However,
low social acceptance levels stand as problematic risk factors regarding social
interaction
Dynamical Boson Stars
The idea of stable, localized bundles of energy has strong appeal as a model
for particles. In the 1950s John Wheeler envisioned such bundles as smooth
configurations of electromagnetic energy that he called {\em geons}, but none
were found. Instead, particle-like solutions were found in the late 1960s with
the addition of a scalar field, and these were given the name {\em boson
stars}. Since then, boson stars find use in a wide variety of models as sources
of dark matter, as black hole mimickers, in simple models of binary systems,
and as a tool in finding black holes in higher dimensions with only a single
killing vector. We discuss important varieties of boson stars, their dynamic
properties, and some of their uses, concentrating on recent efforts.Comment: 79 pages, 25 figures, invited review for Living Reviews in
Relativity; major revision in 201
Protein desulfurization: Sodium tetraethylborate makes it fast
International audienceToday, the development of powerful one-pot techniques combining native chemical ligation and cysteine reductive desulfurization is central to the production of proteins by chemical synthesis. In the September issue of Chem, Xuechen Li and co-workers achieved this goal by combining sodium tetraethylborate and a phosphine as a post-ligation treatment
Strategies and open questions in solid-phase protein chemical synthesis
International audienc
Thiol Catalysis of Selenosulfide Bond Cleavage by a Triarylphosphine
International audienceThe arylthiol 4-mercaptophenylacetic acid (MPAA) is a powerful catalyst of selenosulfide bond reduction by the triarylphosphine 3,3′,3″-phosphanetriyltris(benzenesulfonic acid) trisodium salt (TPPTS). Both reagents are water-soluble at neutral pH and are particularly adapted for working with unprotected peptidic substrates. Contrary to trialkylphosphines such as tris(2-carboxyethyl)phosphine hydrochloride (TCEP), TPPTS has the advantage of not inducing deselenization reactions. We believe that the work reported here will be of value for those manipulating selenosulfide bonds in peptidic or protein molecules
Thiol catalysis of selenosulfide bond cleavage by a triarylphosphine
The arylthiol 4-mercaptophenylacetic acid (MPAA) is a powerful catalyst of selenosulfide bond reduction by the triarylphosphine 3,3′,3′′-phosphanetriyltris(benzenesulfonic acid) trisodium salt (TPPTS). Both reagents are water-soluble at neutral pH and are particularly adapted for working with unprotected peptidic substrates. Contrary to trialkylphosphines such as tris(2-carboxyethyl)phosphine hydrochloride (TCEP), TPPTS has the advantage of not inducing deselenization reactions. We believe that the work reported here will be of value for those manipulating selenosulfide bonds in peptidic or protein molecules
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