Mechanisms of monomeric and dimeric glycogenin autoglucosylation

Initiation of glucose polymerization by glycogenin autoglucosylation at Tyr-194 is required to prime de novo biosynthesis of glycogen. It has been proposed that the synthesis of the primer proceeds by intersubunit glucosylation of dimeric glycogenin, even though it has not been demonstrated that this mechanism is responsible for the described polymerization extent of 12 glucoses produced by the dimer. We reported previously the intramonomer glucosylation capability of glycogenin without determining the extent of autoglucopolymerization. Here, we show that the maximum specific autoglucosylation extent (MSAE) produced by the non-glucosylated glycogenin monomer is 13.3 ± 1.9 glucose units, similar to the 12.5 ± 1.4 glucose units measured for the dimer. The mechanism and capacity of the dimeric enzyme to carry out full glucopolymerization were also evaluated by construction of heterodimers able to glucosylate exclusively by intrasubunit or intersubunit reaction mechanisms. The MSAE of non-glucosylated glycogenin produced by dimer intrasubunit glucosylation was 16% of that produced by the monomer. However, partially glucosylated glycogenin was able to almost complete its autoglucosylation by the dimer intrasubunit mechanism. The MSAE produced by heterodimer intersubunit glucosylation was 60% of that produced by the wild-type dimer. We conclude that both intrasubunit and intersubunit reaction mechanisms are necessary for the dimeric enzyme to acquire maximum autoglucosylation. The full glucopolymerization capacity of monomeric glycogenin indicates that the enzyme is able to synthesize the glycogen primer without the need for prior dimerization.Fil: Issoglio, Federico Matías. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Centro de Investigaciones en Química Biológica de Córdoba. Universidad Nacional de Córdoba. Facultad de Ciencias Químicas. Centro de Investigaciones en Química Biológica de Córdoba; ArgentinaFil: Carrizo Garcia, Maria Elena. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Centro de Investigaciones en Química Biológica de Córdoba. Universidad Nacional de Córdoba. Facultad de Ciencias Químicas. Centro de Investigaciones en Química Biológica de Córdoba; ArgentinaFil: Romero, Jorge Miguel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Centro de Investigaciones en Química Biológica de Córdoba. Universidad Nacional de Córdoba. Facultad de Ciencias Químicas. Centro de Investigaciones en Química Biológica de Córdoba; ArgentinaFil: Curtino, Juan Agustin. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Centro de Investigaciones en Química Biológica de Córdoba. Universidad Nacional de Córdoba. Facultad de Ciencias Químicas. Centro de Investigaciones en Química Biológica de Córdoba; Argentin

Crystal structure of Trypanosoma cruzi heme peroxidase and characterization of its substrate specificity and compound I intermediate

The protozoan parasite Trypanosoma cruzi is the causative agent of American trypanosomiasis, otherwise known as Chagas disease. To survive in the host, the T. cruzi parasite needs antioxidant defense systems. One of these is a hybrid heme peroxidase, the T. cruzi ascorbate peroxidase-cytochrome c peroxidase enzyme (TcAPx-CcP). TcAPx-CcP has high sequence identity to members of the class I peroxidase family, notably ascorbate peroxidase (APX) and cytochrome c peroxidase (CcP), as well as a mitochondrial peroxidase from Leishmania major (LmP). The aim of this work was to solve the structure and examine the reactivity of the TcAPx-CcP enzyme. Low temperature electron paramagnetic resonance spectra support the formation of an exchange-coupled [Fe(IV)=O Trp233•+] compound I radical species, analogous to that used in CcP and LmP. We demonstrate that TcAPx-CcP is similar in overall structure to APX and CcP, but there are differences in the substrate-binding regions. Furthermore, the electron transfer pathway from cytochrome c to the heme in CcP and LmP is preserved in the TcAPx-CcP structure. Integration of steady state kinetic experiments, molecular dynamic simulations, and bioinformatic analyses indicates that TcAPx-CcP preferentially oxidizes cytochrome c but is still competent for oxidization of ascorbate. The results reveal that TcAPx-CcP is a credible cytochrome c peroxidase, which can also bind and use ascorbate in host cells, where concentrations are in the millimolar range. Thus, kinetically and functionally TcAPx-CcP can be considered a hybrid peroxidase.Fil: Freeman, Samuel L.. University of Bristol; Reino UnidoFil: Skafar, Vera. Universidad de la República; UruguayFil: Kwon, Hanna. University of Leicester; Reino UnidoFil: Fielding, Alistair J.. Liverpool John Moores University; Reino UnidoFil: Moody, Peter C.E.. University of Leicester; Reino UnidoFil: Martínez, Alejandra. Universidad de la República; UruguayFil: Issoglio, Federico Matías. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Química Biológica de la Facultad de Ciencias Exactas y Naturales. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Química Biológica de la Facultad de Ciencias Exactas y Naturales; Argentina. Universidade Nova de Lisboa; PortugalFil: Inchausti, Lucas. Universidad de la Republica; Uruguay. Instituto de Investigaciones Biológicas "Clemente Estable"; UruguayFil: Smircich, Pablo. Instituto de Investigaciones Biológicas "Clemente Estable"; Uruguay. Universidad de la Republica; UruguayFil: Zeida, Ari. Universidad de la Republica; UruguayFil: Piacenza, Lucía. Universidad de la Republica; UruguayFil: Radi, Rafael. Universidad de la Republica; UruguayFil: Raven, Emma L.. University of Bristol; Reino Unid

Estudios estructurales y bioquímicos de enzimas y reacciones de iniciación de la biosíntesis de proteoglucógeno

Tesis (Doctor en Ciencias Químicas) - - Universidad Nacional de Córdoba. Facultad de Ciencias Químicas, 2014Fil: Issoglio, Federico Matías. Universidad Nacional de Córdoba. Facultad de Ciencias Químicas; Argentina.En mamíferos la biosíntesis de novo de glucógeno comienza con la acción de una enzima llamada glucogenina, que es capaz de incorporar sobre sí misma, de manera autocatalítica, una molécula de glucosa, a través de la formación de un enlace Oglicosídico entre un residuo tirosina y el extremo reductor de la glucosa (a-1-0-Tyr). Además, puede catalizar un segundo proceso químicamente diferente, la incorporación sucesiva de glucosas mediante la formación de enlaces a-(1 -.4), formando así un oligoglucano lineal sobre el que actúan las enzimas glucógeno sintasa (GS) y ramificante (GBE) para dar lugar a una nueva molécula de proteoglucó geno. Aquí se presentan los resultados obtenidos a partir de estudios relacionados con la estructura y función de glucogenina y GBE, dos de los tres actores principales en la biosíntesis de novo del glucógeno. En particular, en este trabajo de tesis doctoral se profundizó en el conocimiento acerca del mecanismo por el cual la autoglucosilación de glucogenina genera el oligoglucano necesario para que se inicie la biosíntesis de novo del glucógeno. Hace unos años se había demostrado que el dímero de glucogenina tiene la capacidad de autoglucosilarse mediante un mecanismo de glucosilación intersubunidad, y nuestro lb grupo había aportado evidencias de que el monómero era capaz de autoglucosilarse, sugiriendo que el dímero podía glucosilarse por un mecanismo intrasubunidad. A través del diseño de experimentos que incluyeron la mezcla de mutantes de glucogenina inactivas para la catálisis o incapaces de funcionar como sustrato aceptor de glucosa, en este trabajo de tesis doctoral se pudo revelar que ambos mecanismos, intra- e intersubunidad, se complementan en el dímero para alcanzar el máximo grado de autoglucosilación. También se analizó la posibilidad de que el monómero de glucogenina sea capaz de generar un oligoglucano que pueda ser utilizado como sustrato por las enzimas GS y GBE para dar lugar a una nueva molécula de glucógeno madura. En el caso de la enzima ramificante del glucógeno es menor la cantidad de datos de que se dispone acerca de su mecanismo de acción, y muchos de los informes al respecto corresponden a enzimas de la familia de glicosil hidrolasas GH13, a la que pertenece GBE, tales como a-amilasas e isoamilasas. Los estudios bioquímicos y cinéticos de GBE publicados hasta el momento fueron realizados con enzimas de origen bacteriano, y algunos de origen vegetal para el caso de la enzima ramificante del almidón (SBE). En el segundo capítulo se presentan los primeros resultados de la caracterización de GBE humana, que incluyen el perfil de la longitud de las ramas que genera y un estudio cinético de la reacción que cataliza. Por último, se abordó un enfoque bioinformático para tratar de develar el interrogante acerca de cuál es la estructura que glucogenina debe adoptar para superar la distancia de 12-20 A que separa a la tirosina aceptora del UDP-glucosa, y así lograr la incorporación de la primera glucosa que da comienzo a la reacción de autoglucosilación. Para llevar a cabo esto se utilizaron simulaciones de dinámica molecular guiada, con lo que se consiguió obtener detalles a nivel atómico de las interacciones que podrían ser responsables para que el cambio conformacional tenga lugar.Fil: Issoglio, Federico Matías. Universidad Nacional de Córdoba. Facultad de Ciencias Químicas; Argentina

Electron transfer pathways from quantum dynamics simulations

This work explores the possibility of simulating an electron transfer process between a donor and an acceptor in real time using time-dependent density functional theory electron dynamics. To achieve this objective, a central issue to resolve is the definition of the initial state. This must be a non-equilibrium electronic state able to trigger the charge transfer dynamics; here, two schemes are proposed to prepare such states. One is based on the combination of the density matrices of the donor and acceptor converged separately with appropriate charges (for example, −1 for the donor and +1 for the acceptor). The second approach relied on constrained DFT to localize the charge on each fragment. With these schemes, electron transfer processes are simulated in different model systems of increasing complexity: an atomic hydrogen dimer, a polyacetylene chain, and the active site of the T. cruzi hybrid type A heme peroxidase, for which two possible electron transfer paths have been postulated. For the latter system, the present methodology applied in a hybrid Quantum Mechanics - Molecular Mechanics framework allows us to establish the relative probabilities of each path and provides insight into the inhibition of the electron transfer provoked by the substitution of tryptophan by phenylalanine in the W233F mutant.Fil: Pedron, Federico Nicolás. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Química, Física de los Materiales, Medioambiente y Energía. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Química, Física de los Materiales, Medioambiente y Energía; Argentina. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Química Inorgánica, Analítica y Química Física; ArgentinaFil: Issoglio, Federico Matías. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Química Biológica de la Facultad de Ciencias Exactas y Naturales. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Química Biológica de la Facultad de Ciencias Exactas y Naturales; Argentina. Universidade Nova de Lisboa; PortugalFil: Estrin, Dario Ariel. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Química, Física de los Materiales, Medioambiente y Energía. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Química, Física de los Materiales, Medioambiente y Energía; Argentina. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Química Inorgánica, Analítica y Química Física; ArgentinaFil: Scherlis Perel, Damian Ariel. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Química, Física de los Materiales, Medioambiente y Energía. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Química, Física de los Materiales, Medioambiente y Energía; Argentina. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Química Inorgánica, Analítica y Química Física; Argentin

3-Nitrotyrosine and related derivatives in proteins: precursors, radical intermediates and impact in function

Abstract Oxidative post-translational modification of proteins by molecular oxygen (O2)- and nitric oxide (•NO)-derived reactive species is a usual process that occurs in mammalian tissues under both physiological and pathological conditions and can exert either regulatory or cytotoxic effects. Although the side chain of several amino acids is prone to experience oxidative modifications, tyrosine residues are one of the preferred targets of one-electron oxidants, given the ability of their phenolic side chain to undergo reversible one-electron oxidation to the relatively stable tyrosyl radical. Naturally occurring as reversible catalytic intermediates at the active site of a variety of enzymes, tyrosyl radicals can also lead to the formation of several stable oxidative products through radical–radical reactions, as is the case of 3-nitrotyrosine (NO2Tyr). The formation of NO2Tyr mainly occurs through the fast reaction between the tyrosyl radical and nitrogen dioxide (•NO2). One of the key endogenous nitrating agents is peroxynitrite (ONOO−), the product of the reaction of superoxide radical (O2•−) with •NO, but ONOO−-independent mechanisms of nitration have been also disclosed. This chemical modification notably affects the physicochemical properties of tyrosine residues and because of this, it can have a remarkable impact on protein structure and function, both in vitro and in vivo. Although low amounts of NO2Tyr are detected under basal conditions, significantly increased levels are found at pathological states related with an overproduction of reactive species, such as cardiovascular and neurodegenerative diseases, inflammation and aging. While NO2Tyr is a well-established stable oxidative stress biomarker and a good predictor of disease progression, its role as a pathogenic mediator has been laboriously defined for just a small number of nitrated proteins and awaits further studies.</jats:p

Crystal structure and mutational analysis of the human TRIM7 B30.2 domain provide insights into the molecular basis of its binding to glycogenin-1

Tripartite motif (TRIM)7 is an E3 ubiquitin ligase that was first identified through its interaction with glycogenin-1 (GN1), the autoglucosyltransferase that initiates glycogen biosynthesis. A growing body of evidence indicates that TRIM7 plays an important role in cancer development, viral pathogenesis, and atherosclerosis and, thus, represents a potential therapeutic target. TRIM family proteins share a multidomain architecture with a conserved N-terminal TRIM and a variable C-terminal domain. Human TRIM7 contains the canonical TRIM motif and a B30.2 domain at the C terminus. To contribute to the understanding of the mechanism of action of TRIM7, we solved the X-ray crystal structure of its B30.2 domain (TRIM7B30.2) in two crystal forms at resolutions of 1.6 Å and 1.8 Å. TRIM7B30.2 exhibits the typical B30.2 domain fold, consisting of two antiparallel β-sheets of seven and six strands, arranged as a distorted β-sandwich. Furthermore, two long loops partially cover the concave face of the β-sandwich defined by the β-sheet of six strands, thus forming a positively charged cavity. We used sequence conservation and mutational analyses to provide evidence of a putative binding interface for GN1. These studies showed that Leu423, Ser499, and Cys501 of TRIM7B30.2 and the C-terminal 33 amino acids of GN1 are critical for this binding interaction. Molecular dynamics simulations also revealed that hydrogen bond and hydrophobic interactions play a major role in the stability of a modeled TRIM7B30.2-GN1 C-terminal peptide complex. These data provide useful information that could be used to target this interaction for the development of potential therapeutic agents.Fil: Muñoz Sosa, Christian Javier. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Centro de Investigaciones en Química Biológica de Córdoba. Universidad Nacional de Córdoba. Facultad de Ciencias Químicas. Centro de Investigaciones en Química Biológica de Córdoba; ArgentinaFil: Issoglio, Federico Matías. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Química Biológica de la Facultad de Ciencias Exactas y Naturales. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Química Biológica de la Facultad de Ciencias Exactas y Naturales; ArgentinaFil: Carrizo Villar, María Eva. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Centro de Investigaciones en Química Biológica de Córdoba. Universidad Nacional de Córdoba. Facultad de Ciencias Químicas. Centro de Investigaciones en Química Biológica de Córdoba; Argentin

Structural and biochemical insight into glycogenin inactivation by the glycogenosis-causing T82M mutation

AbstractThe X-ray structure of rabbit glycogenin containing the T82M (T83M according to previous authors amino acid numbering [1]) mutation causing glycogenosis showed the loss of Thr82 hydrogen bond to Asp162, the residue involved in the activation step of the glucose transfer reaction mechanism. Autoglucosylation, maltoside transglucosylation and UDP-glucose hydrolyzing activities were abolished even though affinity and interactions with UDP-glucose and positioning of Tyr194 acceptor were conserved. Substitution of Thr82 for serine but not for valine restored the maximum extent of autoglucosylation as well as transglucosylation and UDP-glucose hydrolysis rate. Results provided evidence sustaining the essential role of the lost single hydrogen bond for UDP-glucose activation leading to glycogenin-bound glycogen primer synthesis

Multiple oxidative post-translational modifications of human glutamine synthetase mediate peroxynitrite-dependent enzyme inactivation and aggregation

Funding Information: This work was supported by grants of Universidad de la República (CSIC_2018 and EI_2020) to R. R., Universidad de la República (CSIC Iniciación_2017_ID_159) to N. C., Alexander von Humboldt Foundation (AvHF) to T. G. and R. R., the Novo Nordisk Foundation ( NNF13OC0004294 and NNF20SA0064214 ) to M. J. D., and PICT 2018-0795 from Agencia I+d+i Argentina , University of Buenos Aires (grant 20020120300025BA ), and CONICET (grant 11220150100303CO ) to D. E. N. C. was partially supported by a fellowship from Comisión Académica de Posgrado (CAP), Universidad de la República , Uruguay. Additional funding was obtained from Programa de Desarrollo de las Ciencias Básicas (PEDECIBA, Uruguay), Agencia Nacional de Investigación e Innovación (ANII-SNI, Uruguay), EU-LAC Health (EULACH16/T01-0131), and Programa de Alimentos y Salud Humana (PAyS, Uruguay). Funding Information: The authors would like to thank Dr Tobias Karlberg and Dr Susanne Gräslund from the Karolinska Institutet - Structural Genomics Consortium for providing the HsGS plasmid (Construct ID GLULA-c004). We also thank Dr Verónica Tórtora for her major aid within the initial steps of the transformation and HsGS expression experiments. N. C. D. E. P. H. T. G. M. J. D. S. B. and R. R. conceptualization; N. C. Mauricio Mastrogiovanni, Michele Mariotti, F. M. I. and P. H. methodology; N. C. Mauricio Mastrogiovanni, Michele Mariotti, and F. M. I. investigation; N. C. writing–original draft; M. J. D. S. B. and R. R. writing–review and editing; R. R. supervision. This work was supported by grants of Universidad de la República (CSIC_2018 and EI_2020) to R. R. Universidad de la República (CSIC Iniciación_2017_ID_159) to N. C. Alexander von Humboldt Foundation (AvHF) to T. G. and R. R. the Novo Nordisk Foundation (NNF13OC0004294 and NNF20SA0064214) to M. J. D. and PICT 2018-0795 from Agencia I+d+i Argentina, University of Buenos Aires (grant 20020120300025BA), and CONICET (grant 11220150100303CO) to D. E. N. C. was partially supported by a fellowship from Comisión Académica de Posgrado (CAP), Universidad de la República, Uruguay. Additional funding was obtained from Programa de Desarrollo de las Ciencias Básicas (PEDECIBA, Uruguay), Agencia Nacional de Investigación e Innovación (ANII-SNI, Uruguay), EU-LAC Health (EULACH16/T01-0131), and Programa de Alimentos y Salud Humana (PAyS, Uruguay). Publisher Copyright: © 2023 The AuthorsGlutamine synthetase (GS), which catalyzes the ATP-dependent synthesis of L-glutamine from L-glutamate and ammonia, is a ubiquitous and conserved enzyme that plays a pivotal role in nitrogen metabolism across all life domains. In vertebrates, GS is highly expressed in astrocytes, where its activity sustains the glutamate-glutamine cycle at glutamatergic synapses and is thus essential for maintaining brain homeostasis. In fact, decreased GS levels or activity have been associated with neurodegenerative diseases, with these alterations attributed to oxidative post-translational modifications of the protein, in particular tyrosine nitration. In this study, we expressed and purified human GS (HsGS) and performed an in-depth analysis of its oxidative inactivation by peroxynitrite (ONOO−) in vitro. We found that ONOO− exposure led to a dose-dependent loss of HsGS activity, the oxidation of cysteine, methionine, and tyrosine residues and also the nitration of tryptophan and tyrosine residues. Peptide mapping by LC-MS/MS through combined H216O/H218O trypsin digestion identified up to 10 tyrosine nitration sites and five types of dityrosine cross-links; these modifications were further scrutinized by structural analysis. Tyrosine residues 171, 185, 269, 283, and 336 were the main nitration targets; however, tyrosine-to-phenylalanine HsGS mutants revealed that their sole nitration was not responsible for enzyme inactivation. In addition, we observed that ONOO− induced HsGS aggregation and activity loss. Thiol oxidation was a key modification to elicit aggregation, as it was also induced by hydrogen peroxide treatment. Taken together, our results indicate that multiple oxidative events at various sites are responsible for the inactivation and aggregation of human GS.publishersversionpublishe

3-Nitrotyrosine and related derivatives in proteins: precursors, radical intermediates and impact in function

Oxidative post-translational modification of proteins by molecular oxygen (O2)- and nitric oxide (•NO)-derived reactive species is a usual process that occurs in mammalian tissues under both physiological and pathological conditions and can exert either regulatory or cytotoxic effects. Although the side chain of several amino acids is prone to experience oxidative modifications, tyrosine residues are one of the preferred targets of one-electron oxidants, given the ability of their phenolic side chain to undergo reversible one-electron oxidation to the relatively stable tyrosyl radical. Naturally occurring as reversible catalytic intermediates at the active site of a variety of enzymes, tyrosyl radicals can also lead to the formation of several stable oxidative products through radical–radical reactions, as is the case of 3-nitrotyrosine (NO2Tyr). The formation of NO2Tyr mainly occurs through the fast reaction between the tyrosyl radical and nitrogen dioxide (•NO2). One of the key endogenous nitrating agents is peroxynitrite (ONOO−), the product of the reaction of superoxide radical (O2•−) with •NO, but ONOO−-independent mechanisms of nitration have been also disclosed. This chemical modification notably affects the physicochemical properties of tyrosine residues and because of this, it can have a remarkable impact on protein structure and function, both in vitro and in vivo. Although low amounts of NO2Tyr are detected under basal conditions, significantly increased levels are found at pathological states related with an overproduction of reactive species, such as cardiovascular and neurodegenerative diseases, inflammation and aging. While NO2Tyr is a well-established stable oxidative stress biomarker and a good predictor of disease progression, its role as a pathogenic mediator has been laboriously defined for just a small number of nitrated proteins and awaits further studies.Fil: Campolo, Nicolás. Universidad de la República; UruguayFil: Issoglio, Federico Matías. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Química Biológica de la Facultad de Ciencias Exactas y Naturales. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Química Biológica de la Facultad de Ciencias Exactas y Naturales; ArgentinaFil: Estrin, Dario Ariel. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Química, Física de los Materiales, Medioambiente y Energía. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Química, Física de los Materiales, Medioambiente y Energía; ArgentinaFil: Bartesaghi Hierro, Silvina María. Universidad de la República; UruguayFil: Radi, Rafael. Universidad de la República; Urugua