Echinococosis de Fémur

El primer caso de equinococosis ósea es el de Cullerier, descripto por Gangolphe, de 1801. Se trataba de un tumor del tercio superior de la pierna, que al abrirlo revela la presencia de vesículas hidáticas, los acefalocistos de Iaennec. En 1838, Dezeimeris J.S. publica el primer estudio, con revisión general, consagrado al tema, en el que figura unguaso de fémur, siendo éste el primero que puede recogerse en la literatura.Material digitalizado en SEDICI gracias a la colaboración de la Biblioteca de la Facultad de Ciencias Médicas (UNLP).Facultad de Ciencias Médica

Presentación de cara: estadísticas de la maternidad de La Plata desde los años 1936 a 1945

Es menester analizar en forma sumaria las principales características de esta presentación para tener idea de las distocias que pueden presentarse y hacer luego el estudio de parto eutócicos y distócicos y dentro de estos, cuáles han sido las eventualidades más frecuentes y como han sido resueltos en diez años de (de 1936 a 1945) en la Maternidad de La Plata.Tesis digitalizada en SEDICI gracias a la Biblioteca de la Facultad de Ciencias Médicas (UNLP).Facultad de Ciencias Médica

New insights into the enzymatic mechanism of human chitotriosidase (CHIT1) catalytic domain by atomic resolution X-ray diffraction and hybrid QM/MM

Chitotriosidase (CHIT1) is a human chitinase belonging to the highly conserved glycosyl hydrolase family 18 (GH18). GH18 enzymes hydrolyze chitin, an N-acetylglucosamine polymer synthesized by lower organisms for structural purposes. Recently, CHIT1 has attracted attention owing to its upregulation in immune-system disorders and as a marker of Gaucher disease. The 39 kDa catalytic domain shows a conserved cluster of three acidic residues, Glu140, Asp138 and Asp136, involved in the hydrolysis reaction. Under an excess concentration of substrate, CHIT1 and other homologues perform an additional activity, transglycosylation. To understand the catalytic mechanism of GH18 chitinases and the dual enzymatic activity, the structure and mechanism of CHIT1 were analyzed in detail. The resolution of the crystals of the catalytic domain was improved from 1.65 Å (PDB entry 1waw ) to 0.95-1.10 Å for the apo and pseudo-apo forms and the complex with chitobiose, allowing the determination of the protonation states within the active site. This information was extended by hybrid quantum mechanics/molecular mechanics (QM/MM) calculations. The results suggest a new mechanism involving changes in the conformation and protonation state of the catalytic triad, as well as a new role for Tyr27, providing new insights into the hydrolysis and transglycosylation activities.Fil: Fadel, Firas. Centre National de la Recherche Scientifique; Francia. Institut de Génétique et de Biologie Moléculaire et Cellulaire; FranciaFil: Zhao, Yuguang. University of Oxford; Reino UnidoFil: Cachau, Raul. Frederick National Laboratory for Cancer Research; Estados UnidosFil: Cousido Siah, Alexandra. Centre National de la Recherche Scientifique; Francia. Institut de Génétique et de Biologie Moléculaire et Cellulaire; FranciaFil: Ruiz, Francesc X.. Centre National de la Recherche Scientifique; Francia. Institut de Génétique et de Biologie Moléculaire et Cellulaire; FranciaFil: Harlos, Karl. University of Oxford; Reino UnidoFil: Howard, Eduardo Ignacio. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Física de Líquidos y Sistemas Biológicos. Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Instituto de Física de Líquidos y Sistemas Biológicos; Argentina. Centre National de la Recherche Scientifique; Francia. Institut de Génétique et de Biologie Moléculaire et Cellulaire; FranciaFil: Mitschler, Andre. Centre National de la Recherche Scientifique; Francia. Institut de Génétique et de Biologie Moléculaire et Cellulaire; FranciaFil: Podjarny, Alberto Daniel. Centre National de la Recherche Scientifique; Francia. Institut de Génétique et de Biologie Moléculaire et Cellulaire; Franci

New insights into the enzymatic mechanism of human chitotriosidase (CHIT1) catalytic domain by atomic resolution X-ray diffraction and hybrid QM/MM

Chitotriosidase (CHIT1) is a human chitinase belonging to the highly conserved glycosyl hydrolase family 18 (GH18). GH18 enzymes hydrolyze chitin, an N-acetylglucosamine polymer synthesized by lower organisms for structural purposes. Recently, CHIT1 has attracted attention owing to its upregulation in immune-system disorders and as a marker of Gaucher disease. The 39 kDa catalytic domain shows a conserved cluster of three acidic residues, Glu140, Asp138 and Asp136, involved in the hydrolysis reaction. Under an excess concentration of substrate, CHIT1 and other homologues perform an additional activity, transglycosylation. To understand the catalytic mechanism of GH18 chitinases and the dual enzymatic activity, the structure and mechanism of CHIT1 were analyzed in detail. The resolution of the crystals of the catalytic domain was improved from 1.65 Å (PDB entry 1waw ) to 0.95-1.10 Å for the apo and pseudo-apo forms and the complex with chitobiose, allowing the determination of the protonation states within the active site. This information was extended by hybrid quantum mechanics/molecular mechanics (QM/MM) calculations. The results suggest a new mechanism involving changes in the conformation and protonation state of the catalytic triad, as well as a new role for Tyr27, providing new insights into the hydrolysis and transglycosylation activities.Instituto de Física de Líquidos y Sistemas Biológico

Structural Basis of Outstanding Multivalent Effects in Jack Bean α-Mannosidase Inhibition

Multivalent design of glycosidase inhibitors is a promising strategy for the treatment of diseases involving enzymatic hydrolysis of glycosidic bonds in carbohydrates. An essential prerequisite for successful applications is the atomic‐level understanding of how outstanding binding enhancement occurs with multivalent inhibitors. Herein we report the first high‐resolution crystal structures of the Jack bean α‐mannosidase (JBα‐man) in apo and inhibited states. The three‐dimensional structure of JBα‐man in complex with the multimeric cyclopeptoid‐based inhibitor displaying the largest binding enhancements reported so far provides decisive insight into the molecular mechanisms underlying multivalent effects in glycosidase inhibition.Instituto de Física de Líquidos y Sistemas Biológico

High-resolution neutron and X-ray diffraction room-temperature studies of an H-FABP-oleic acid complex: study of the internal water cluster and ligand binding by a transferred multipolar electron-density distribution

Crystal diffraction data of heart fatty acid binding protein (H-FABP) in complex with oleic acid were measured at room temperature with high-resolution X-ray and neutron protein crystallography (0.98 and 1.90 Å resolution, respectively). These data provided very detailed information about the cluster of water molecules and the bound oleic acid in the H-FABP large internal cavity. The jointly refined X-ray/neutron structure of H-FABP was complemented by a transferred multipolar electron-density distribution using the parameters of the ELMAMII library. The resulting electron density allowed a precise determination of the electrostatic potential in the fatty acid (FA) binding pocket. Bader's quantum theory of atoms in molecules was then used to study interactions involving the internal water molecules, the FA and the protein. This approach showed H···H contacts of the FA with highly conserved hydrophobic residues known to play a role in the stabilization of long-chain FAs in the binding cavity. The determination of water hydrogen (deuterium) positions allowed the analysis of the orientation and electrostatic properties of the water molecules in the very ordered cluster. As a result, a significant alignment of the permanent dipoles of the water molecules with the protein electrostatic field was observed. This can be related to the dielectric properties of hydration layers around proteins, where the shielding of electrostatic interactions depends directly on the rotational degrees of freedom of the water molecules in the interface.Facultad de Ciencias ExactasInstituto de Física de Líquidos y Sistemas Biológico

Structural variability of E. coli thioredoxin captured in the crystal structures of single-point mutants

Thioredoxin is a ubiquitous small protein that catalyzes redox reactions of protein thiols. Additionally, thioredoxin from E. coli (EcTRX) is a widely-used model for structure-function studies. In a previous paper, we characterized several single-point mutants of the C-terminal helix (CTH) that alter global stability of EcTRX. However, spectroscopic signatures and enzymatic activity for some of these mutants were found essentially unaffected. A comprehensive structural characterization at the atomic level of these near-invariant mutants can provide detailed information about structural variability of EcTRX. We address this point through the determination of the crystal structures of four point-mutants, whose mutations occurs within or near the CTH, namely L94A, E101G, N106A and L107A. These structures are mostly unaffected compared with the wild-type variant. Notably, the E101G mutant presents a large region with two alternative traces for the backbone of the same chain. It represents a significant shift in backbone positions. Enzymatic activity measurements and conformational dynamics studies monitored by NMR and molecular dynamic simulations show that E101G mutation results in a small effect in the structural features of the protein. We hypothesize that these alternative conformations represent samples of the native-state ensemble of EcTRX, specifically the magnitude and location of conformational heterogeneity.Fil: Noguera, Martín Ezequiel. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Química y Físico-Química Biológicas "Prof. Alejandro C. Paladini". Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica. Instituto de Química y Físico-Química Biológicas; ArgentinaFil: Vazquez, Diego Sebastian. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Química y Físico-Química Biológicas "Prof. Alejandro C. Paladini". Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica. Instituto de Química y Físico-Química Biológicas; ArgentinaFil: Ferrer Sueta, Gerardo. Universidad de la República; UruguayFil: Agudelo Suarez, William Armando. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Química y Físico-Química Biológicas "Prof. Alejandro C. Paladini". Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica. Instituto de Química y Físico-Química Biológicas; ArgentinaFil: Howard, Eduardo Ignacio. Université de Strasbourg; Francia. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Rasia, Rodolfo Maximiliano. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Rosario. Instituto de Biología Molecular y Celular de Rosario. Universidad Nacional de Rosario. Facultad de Ciencias Bioquímicas y Farmacéuticas. Instituto de Biología Molecular y Celular de Rosario; ArgentinaFil: Manta, Bruno. Universidad de la República; UruguayFil: Cousido Siah, Alexandra. Université de Strasbourg; FranciaFil: Mitschler, André. Université de Strasbourg; FranciaFil: Podjarny, Alberto Daniel. Université de Strasbourg; FranciaFil: Santos, Javier. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Química y Físico-Química Biológicas "Prof. Alejandro C. Paladini". Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica. Instituto de Química y Físico-Química Biológicas; Argentin

Structural variability of E. coli thioredoxin captured in the crystal structures of single-point mutants

Thioredoxin is a ubiquitous small protein that catalyzes redox reactions of protein thiols. Additionally, thioredoxin from E. coli (EcTRX) is a widely-used model for structure-function studies. In a previous paper, we characterized several single-point mutants of the C-terminal helix (CTH) that alter global stability of EcTRX. However, spectroscopic signatures and enzymatic activity for some of these mutants were found essentially unaffected. A comprehensive structural characterization at the atomic level of these near-invariant mutants can provide detailed information about structural variability of EcTRX. We address this point through the determination of the crystal structures of four point-mutants, whose mutations occurs within or near the CTH, namely L94A, E101G, N106A and L107A. These structures are mostly unaffected compared with the wild-type variant. Notably, the E101G mutant presents a large region with two alternative traces for the backbone of the same chain. It represents a significant shift in backbone positions. Enzymatic activity measurements and conformational dynamics studies monitored by NMR and molecular dynamic simulations show that E101G mutation results in a small effect in the structural features of the protein. We hypothesize that these alternative conformations represent samples of the native-state ensemble of EcTRX, specifically the magnitude and location of conformational heterogeneity

Discovery of (R)-2-Amino-6-borono-2-(2-(piperidin-1-yl)ethyl)hexanoic Acid and Congeners As Highly Potent Inhibitors of Human Arginases I and II for Treatment of Myocardial Reperfusion Injury

Recent efforts to identify treatments for myocardial ischemia reperfusion injury have resulted in the discovery of a novel series of highly potent α,α-disubstituted amino acid-based arginase inhibitors. The lead candidate, (R)-2-amino-6-borono-2-(2-(piperidin-1-yl)ethyl)hexanoic acid, compound 9, inhibits human arginases I and II with IC50s of 223 and 509 nM, respectively, and is active in a recombinant cellular assay overexpressing human arginase I (CHO cells). It is 28% orally bioavailable and significantly reduces the infarct size in a rat model of myocardial ischemia/reperfusion injury. Herein, we report the design, synthesis, and structure−activity relationships (SAR) for this novel series of inhibitors along with pharmacokinetic and in vivo efficacy data for compound 9 and X-ray crystallography data for selected lead compounds cocrystallized with arginases I and II.Fil: Van Zandt, Michael C.. Institutes for Pharmaceutical Discovery; Estados UnidosFil: Whitehouse, Darren L.. Institutes for Pharmaceutical Discovery; Estados UnidosFil: Golebiowski, Adam. Institutes for Pharmaceutical Discovery; Estados UnidosFil: Ji, Min Koo. Institutes for Pharmaceutical Discovery; Estados UnidosFil: Zhang, Mingbao. Institutes for Pharmaceutical Discovery; Estados UnidosFil: Beckett, R. Paul. Institutes for Pharmaceutical Discovery; Estados UnidosFil: Jagdmann, G. Erik. Institutes for Pharmaceutical Discovery; Estados UnidosFil: Ryder, Todd R.. Institutes for Pharmaceutical Discovery; Estados UnidosFil: Sheeler, Ryan. Institutes for Pharmaceutical Discovery; Estados UnidosFil: Andreoli, Monica. Institutes for Pharmaceutical Discovery; Estados UnidosFil: Conway, Bruce. Institutes for Pharmaceutical Discovery; Estados UnidosFil: Mahboubi, Keyvan. Institutes for Pharmaceutical Discovery; Estados UnidosFil: D’Angelo, Gerard. Institutes for Pharmaceutical Discovery; Estados UnidosFil: Mitschler, Andre. Université de Strasbourg; FranciaFil: Cousido Siah, Alexandra. Université de Strasbourg; FranciaFil: Ruiz, Frances X.. Université de Strasbourg; FranciaFil: Howard, Eduardo Ignacio. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Física de Líquidos y Sistemas Biológicos. Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Instituto de Física de Líquidos y Sistemas Biológicos; Argentina. Université de Strasbourg; FranciaFil: Podjarny, Alberto Daniel. Université de Strasbourg; FranciaFil: Schroeter, Hagen. Mars Incorporated; Estados Unido

Identification of a novel polyfluorinated compound as a lead to inhibit human enzymes aldose reductase and AKR1B10 : structure determination of both ternary complexes and implications for drug design

Aldo-keto reductases (AKRs) are mostly monomeric enzymes which fold into a highly conserved ([alpha]/[beta])8 barrel, while their substrate specificity and inhibitor selectivity are determined by interaction with residues located in three highly variable external loops. The closely related human enzymes aldose reductase (AR or AKR1B1) and AKR1B10 are of biomedical interest because of their involvement in secondary diabetic complications (AR) and in cancer, e.g. hepatocellular carcinoma and smoking-related lung cancer (AKR1B10). After characterization of the IC50 values of both AKRs with a series of polyhalogenated compounds, 2,2',3,3',5,5',6,6'-octafluoro-4,4'-biphenyldiol (JF0064) was identified as a lead inhibitor of both enzymes with a new scaffold (a 1,1'-biphenyl-4,4'-diol). An ultrahigh-resolution X-ray structure of the AR-­NADP+-JF0064 complex has been determined at 0.85 Å resolution, allowing it to be observed that JF0064 interacts with the catalytic residue Tyr48 through a negatively charged hydroxyl group (i.e. the acidic phenol). The non-competitive inhibition pattern observed for JF0064 with both enzymes suggests that this acidic hydroxyl group is also present in the case of AKR1B10. Moreover, the combination of surface lysine methylation and the introduction of K125R and V301L mutations enabled the determination of the X-ray crystallo­graphic structure of the corresponding AKR1B10-NADP+-JF0064 complex. Comparison of the two structures has unveiled some important hints for subsequent structure-based drug-design efforts