RESUMO
Understanding of protein-urea interactions is one of the greatest challenges to modern structural protein chemistry. Based in enzyme kinetics experiments and (1)H NMR spectroscopic analysis we proposed that urea, at low concentrations, directly interacts with the protonated histidines of the active center of RNase A, following a simple model of competitive inhibition. These results were supported by theoretical analysis based on the frontier molecular orbital theory and suggest that urea might establish a favorable interaction with the cationic amino acids. Our experimental evidence and theoretical analysis indicate that the initials steps of the molecular mechanism of Urea-RNase A interaction passes through the establishment of a three center four electron adduct. Also, our results would explain the observed disruption of the (1)H NMR signals corresponding to H12 and H119 (involved in catalysis) of the RNase A studied in the presence of urea. Our interaction model of urea-amino acids (cationic) can be extended to explain the inactivation of other enzymes with cationic amino acids at the active site.
Assuntos
Ribonuclease Pancreático/química , Ureia/química , Animais , Biocatálise , Bovinos , Cinética , Espectroscopia de Ressonância Magnética , Modelos Moleculares , Estrutura Molecular , Desnaturação ProteicaRESUMO
La presente tesis pretende contribuir al tema de la identidad en el campo de las prácticas culturales entre los migrantes aymaras que viven en la ciudad de La Paz. Las prácticas culturales que desarrollan los migrantes aymaras como espacios importantes para la reproducción de su identidad. Además, en el medio urbano estas se constituyen en un cohesionador cultural interno del grupo de migrantes aymaras carabuqueños