Institute Biocomputacion Y Fisica Of Los Sistemas Complejos Bifi

Zaragoza, Spain

Institute Biocomputacion Y Fisica Of Los Sistemas Complejos Bifi

Zaragoza, Spain
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Ruiz-Lorenzo J.J.,University of Extremadura | Ruiz-Lorenzo J.J.,Institute Biocomputacion Y Fisica Of Los Sistemas Complejos Bifi
Condensed Matter Physics | Year: 2017

We explicitly compute the critical exponents associated with logarithmic corrections (the so-called hatted exponents) starting from the renormalization group equations and the mean 1eld behavior for a wide class of models at the upper critical behavior (for short and long range φn-theories) and below it. This allows us to check the scaling relations among these critical exponents obtained by analysing the complex singularities (Lee-Yang and Fisher zeroes) of these models. Moreover, we have obtained an explicit method to compute the exponent [de1ned by] and, 1nally, we have found a new derivation of the scaling law associated with it. © J.J. Ruiz-Lorenzo, 2017.

Berski S.,Wrocław University | Sensato F.R.,Federal University of São Paulo | Polo V.,University of Zaragoza | Polo V.,Institute Biocomputacion Y Fisica Of Los Sistemas Complejos Bifi | And 2 more authors.
Journal of Physical Chemistry A | Year: 2011

The oxygen atom transfer reaction from the Mimoun-type complex MoO (η2-O2)2OPH3 to ethylene C 2H4 affording oxirane C2H4O has been investigated within the framework of the Bonding Evolution Theory in which the corresponding molecular mechanism is characterized by the topological analysis of the electron localization function (ELF) and Thom's catastrophe theory (CT). Topological analysis of ELF and electron density analysis reveals that all Mo-O bonds in MoO(η2-O2)2OPH3 and MoO2(η2-O2)OPH3 belong to closed-shell type interactions though negative values of total energy densities Ee(rBCP) imply some covalent contribution. The peroxo Oi-Oj bonds are characterized as charge-shift or protocovalent species in which pairs of monosynaptic basins V3(O i), V3(Opj) with a small electron population of ∼0.25e each, are localized between core basins C(Oi), C(O j). The oxygen transfer reaction from molybdenum diperoxo complex MoO(η2-O2)2OPH3 to C 2H4 system can be described by the following consecutive chemical events: (a) protocovalent peroxo O2-O1 bond breaking, (b) reduction of the double C1=C2 bond to single C1-C2 bond in ethylene, (c) displacement of oxygen O 1 with two nonbonding basins, Vi=1,2(O1), (d) increase of a number of the nonbonding basins to three (V i=1,2,4(O1)); (e) reorganization and reduction in the number of nonbonding basis to two basins (Vi=1,4(O1)) resembling the ELF-topology of the nonbonding electron density in oxirane, (e) formation of the first O1-C2 bond in oxirane, (f) C 2-O1-C2 ring closure, (g) formation of singular nonbonding basin V(O2) in new Mo=O2 bond. The oxygen atom is transferred as an anionic moiety carrying a rather small electronic charge ranging from 0.5 to 0.7e. © 2011 American Chemical Society.

Llusar R.,Jaume I University | Polo V.,Institute Biocomputacion Y Fisica Of Los Sistemas Complejos Bifi | Polo V.,University of Zaragoza | Velez E.,Jaume I University | Vicent C.,Jaume I University
Inorganic Chemistry | Year: 2010

The gas phase fragmentation reactions of sulfur-rich [Mo3S 7Br6]2- (12-), [Mo3S 7(bdt)3]2- (22-), and [Mo 3S4(bdt)3]2- (32-) (bdt = benzenedithiolate) complexes have been investigated by electrospray ionization (ESI) tandem mass spectrometry and theoretical calculations at the density functional theory level. Upon collision induced dissociation (CID) conditions, the brominated 12- dianion dissociates through two sequential steps that involves a heterolytic Mo-Br cleavage to give [Mo3S 7Br5]- plus Br- followed by a two-electron redox process that affords [Mo3S5Br 5]- and diatomic S2 sulfur. Dianion [Mo 3S7(bdt)3]2- (22-) dissociates through two sequential redox processes evolving diatomic S 2 sulfur and neutral bdt to yield [Mo3S 5(bdt)3]2- and [Mo3S 5(bdt)2]2-, respectively. Conversely, dianion [Mo3S4(bdt)3]2- (32-), with sulfide instead of disulfide S2 2- bridged ligands, remains intact under identical fragmentation conditions, thus highlighting the importance of disulfide ligands (S2 2-) as electron reservoirs to trigger redox reactions. Regioselective incorporation of 34S and Se at the equatorial position of the Mo3S 7 cluster core in 12- and 22- have been used to identify the product ions along the fragmentation pathways. Reaction mechanisms for the gas-phase dissociation pathways have been elucidated by means of B3LYP calculations, and a comparison with the solution reactivity of Mo 3S7 and Mo3S4 clusters as well as closely related Mo/S/dithiolene systems is also discussed. © 2010 American Chemical Society.

Espinosa J.,University of Alicante | Lopez-Redondo M.-L.,Institute Biomedicina Of Valencia Csic And Ciberer | Miguel-Romero L.,Institute Biomedicina Of Valencia Csic And Ciberer | Neira J.L.,University Miguel Hernández | And 3 more authors.
Biochimica et Biophysica Acta - Gene Regulatory Mechanisms | Year: 2012

Cyanobacteria respond to environmental stress conditions by adjusting their photosynthesis machinery. In Synechococcus sp. PCC 7942, phycobilisome degradation and other acclimation responses after nutrient or high light stress require activation by the phosphorylation-independent response regulator NblR. Structural modelling of its receiver domain suggested a role for Cys69 and Cys96 on activation of NblR. Here, we investigate this hypothesis by engineering Cys to Ala substitutions. In vivo and in vitro analyses indicated that mutations Cys69Ala and/or Cys96Ala have a minor impact on NblR function, structure, size, or oligomerization state of the protein, and that Cys69 and Cys96 do not seem to form disulphide bridges. Our results argue against the predicted involvement of Cys69 and Cys96 on NblR activation by redox sensing. © 2012 Elsevier B.V..

Marcin W.,Institute Biomedicina Of Valencia | Neira J.L.,University Miguel Hernández | Neira J.L.,Institute Biocomputacion Y Fisica Of Los Sistemas Complejos Bifi | Bravo J.,Institute Biomedicina Of Valencia
PLoS ONE | Year: 2015

Erb1 (Eukaryotic Ribosome Biogenesis 1) protein is essential for the maturation of the ribosomal 60S subunit. Functional studies in yeast and mammalian cells showed that altogether with Nop7 and Ytm1 it forms a stable subcomplex called PeBoW that is crucial for a correct rRNA processing. The exact function of the protein within the process remains unknown. The N-terminal region of the protein includes a well conserved region shown to be involved in PeBoW complex formation whereas the carboxy-terminal half was predicted to contain seven WD40 repeats. This first structural report on Erb1 from yeast describes the architecture of a seven-bladed β-propeller domain that revealed a characteristic extra motif formed by two α-helices and a β-strand that insert within the second WD repeat. We performed analysis of molecular surface and crystal packing, together with multiple sequence alignment and comparison of the structure with other β-propellers, in order to identify areas that are more likely to mediate protein-protein interactions. The abundance of many positively charged residues on the surface of the domain led us to investigate whether the propeller of Erb1 might be involved in RNA binding. Three independent assays confirmed that the protein interacted in vitro with polyuridilic acid (polyU), thus suggesting a possible role of the domain in rRNA rearrangement during ribosome biogenesis. Copyright: © 2015 Marcin et al.

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