Search results for "QM"
showing 10 items of 284 documents
Are Heme-Dependent Enzymes Always Using a Redox Mechanism? A Theoretical Study of the Kemp Elimination Catalyzed by a Promiscuous Aldoxime Dehydratase
2020
The design of biocatalysts is a goal to improve the rate, selectivity and environmental friendship of chemical processes in biotechnology. In this regard, the use of computational techniques has provided valuable assistance in the design of enzymes with remarkable catalytic activity. In this paper, hybrid QM/MM simulations have allowed getting an insight into the mechanism of a promiscuous aldoxime dehydratase (OxdA) for the Kemp elimination. We first demonstrate that, based on the use of linear response approximation (LRA) methods, the lowest energy electronic state of the benzisoxazole placed in the active sit of OxdA corresponds to a singlet state, being the triplet and the quintet state…
On the Nature of the Enzyme–Substrate Complex and the Reaction Mechanism in Human Arginase I. A Combined Molecular Dynamics and QM/MM Study
2020
We present here a detailed theoretical analysis of L-arginine hydrolysis catalyzed by Human Arginase I (HARGI). Our study combines classical molecular dynamic simulations of different model for the...
Why Are Some Enzymes Dimers? Flexibility and Catalysis in Thermotoga maritima Dihydrofolate Reductase
2019
[Image: see text] Dihydrofolate reductase from Thermotoga maritima (TmDFHFR) is a dimeric thermophilic enzyme that catalyzes the hydride transfer from the cofactor NADPH to dihydrofolate less efficiently than other DHFR enzymes, such as the mesophilic analogue Escherichia coli DHFR (EcDHFR). Using QM/MM potentials, we show that the reduced catalytic efficiency of TmDHFR is most likely due to differences in the amino acid sequence that stabilize the M20 loop in an open conformation, which prevents the formation of some interactions in the transition state and increases the number of water molecules in the active site. However, dimerization provides two advantages to the thermophilic enzyme: …
Efectos del compuesto 4QMn en ratones zQ175neo como modelo murino de la enfermedad neurodegenerativa de Huntington
2022
La enfermedad de Huntington (EH) es un grave trastorno neurodegenerativo autosómico dominante caracterizado por una combinación de síntomas motores, cognitivos y psiquiátricos. Su causa es la expansión de una secuencia de repeticiones CAG en el gen HTT, que codifica una versión mutada de la proteína Huntingtina (Yapijakis, 2017). Esta secuencia expandida origina cambios conformacionales que propician la formación de agregados tanto citosólicos como nucleares y, con ello, alteraciones intracelulares, toxicidad y pérdida neuronal (Nance, 2017). La progresión inevitable de la patología resulta en la muerte de las personas con EH entre 5 y 20 años después de la manifestación de sus síntomas (Ka…
An Early Stage Researcher's Primer on Systems Medicine Terminology
2021
Background: Systems Medicine is a novel approach to medicine, that is, an interdisciplinary field that considers the human body as a system, composed of multiple parts and of complex relationships at multiple levels, and further integrated into an environment. Exploring Systems Medicine implies understanding and combining concepts coming from diametral different fields, including medicine, biology, statistics, modeling and simulation, and data science. Such heterogeneity leads to semantic issues, which may slow down implementation and fruitful interaction between these highly diverse fields. Methods: In this review, we collect and explain more than100 terms related to Systems Medicine. Thes…
Empresas excelentes entre las certificadas en las normas ISO 9000
2005
En este trabajo se realiza un estudio entre las empresas certificadas en la norma ISO 9000 de la Comunidad Valenciana mediante una encuesta, con el objetivo de diferenciar los resultados sobre incremento de competitividad por la certificación en las normas ISO 9000, dependiendo de la involucración de las empresas en los sistemas de gestión de la calidad total, así como averiguar que factores inciden para que las empresas certificadas se impliquen en mayor medida en estos sistemas
Datu kvalitātes problemātika un risinājumi sociālās politikas monitoringa informācijas sistēmā
2017
Datu kvalitāte ir nozīmīga jebkurā informācijas sistēmā, jo kļūdas datos var novest pie nepareizu rezultātu iegūšanas vai kļūdainu lēmumu veikšanas. Taču ne visi lietotāji un izstrādātāji apzinās, ka datu kvalitāte būtu jākontrolē. Bakalaura darba mērķis ir aplūkot sociālās politikas monitoringa informācijas sistēmas datu kvalitātes problemātiku un izstrādāt praktisku risinājumu, ar kuru būtu iespējams nodrošināt augstāku datu kvalitāti, bez lietotāju iejaukšanās. Balstoties uz pētījumā veikto pieeju analīzi, izstrādāta minētās sistēmas datu kvalitātes problēmu risināšanas pieeja. Atbilstoši izstrādātajai pieejai, izstrādāta darbvirsmas programma un papildināts esošais tīmekļa pakalpojums, …
Conformational equilibrium of chorismate. A QM/MM theoretical study combining statistical simulations and geometry optimisations in gas phase and in …
2003
We report a theoretical study on the conformational equilibrium of chorismate that precedes its rearrangement to prephenate, an important enzyme-catalyzed reaction. In first place we show that the usual classification of chorismate conformers based on the relative position of the hydroxyl and ether bridge, pseudo-diaxial and pseudo-diequatorial, is not the only relevant factor from the point of view of the a posteriori rearrangement. Here we also analyse another complementary geometrical classification based on the interatomic distance between the carbon atoms to be bounded. Using the umbrella sampling approach and this distance as distinguished internal reaction coordinate, the gas phase A…
Time evolution of non-lethal infectious diseases: a semi-continuous approach.
2005
A model describing the dynamics related to the spreading of non-lethal infectious diseases in a fixed-size population is proposed. The model consists of a non-linear delay-differential equation describing the time evolution of the increment in the number of infectious individuals and depends upon a limited number of parameters. Predictions are in good qualitative agreement with data on influenza.
Material Docente EQM
2018
El document forma part dels materials docents programats mitjançant l'ajut del Servei de Política Lingüística de la Universitat de València. Material docente: transparencias teoría, boletines problemas, PECs, guiones laboratorio,presentación asignatura