RESUMEN
Background: The current study tried to evaluate the quality of life (QOL) of phenylketonuria (PKU) patients residing in Tehran, Iran and it also tried to determine the average quality of life of patients. Various aspects of QOL have been analyzed depending on gender, age, and educational levels of the subjects. Methods: The sample of the study consisted of late-diagnosed PKU patients who were referred to Mofid Children's Medical Center as well as to Ali-Asghar Hospitals in order to receive metabolic diets on a one year period starting from spring 2013 to spring 2014. Due to the limited study population, subjects were selected via census, therefore 82 patients were enrolled. The research material consisted of the Persian edition of World Health Organization Quality of Life questionnaire (WHOQOL-BREF), designed to examine physical, mental, social and environmental health. The data was gathered on two levels-descriptive and inferential- by using the SPSS software, V.20. Results: Results indicated that the low quality of life in the late-diagnosed patients suffering from PKU, with mental, physical, social, and environmental aspects, was below the average. Still, even if it was not gender dependent, QOL was greatly influenced by the educational level of the patients. Moreover, it was discovered that the mental health of the patients above 40 years old was significantly lower than the other age groups. Conclusions: According to the findings of this study, it was recommended that special attention should be given to the improvement of the social and mental health of PKU patients.
RESUMEN
Formyltetrahydrofolate synthetase (FTHFS) from the thermophilic homoacetogen, Moorella thermoacetica, has an optimum temperature for activity of 55-60 degrees C and requires monovalent cations for both optimal activity and stabilization of tetrameric structure at higher temperatures. The crystal structures of complexes of FTHFS with cesium and potassium ions were examined and monovalent cation binding positions identified. Unexpectedly, NH(4)(+) and K(+), both of which are strongly activating ions, bind at a different site than a moderately activating ion, Cs(+), does. Neither binding site is located in the active site. The sites are 7 A apart, but in each of them, the side chain of Glu 98, which is conserved in all known bacterial FTHFS sequences, participates in metal ion binding. Other ligands in the Cs(+) binding site are four oxygen atoms of main chain carbonyls and water molecules. The K(+) and NH(4)(+) binding site includes the carboxylate of Asp132 in addition to Glu98. Mutant FTHFS's (E98Q, E98D, and E98S) were obtained and analyzed using differential scanning calorimetry to examine the effect of these mutations on the thermostability of the enzyme with and without added K(+) ions. The addition of 0.2 M K(+) ions to the wild-type enzyme resulted in a 10 degrees C increase in the thermal denaturation temperature. No significant increase was observed in E98D or E98S. The lack of a significant effect of monovalent cations on the stability of E98D and E98S indicates that this alteration of the binding site eliminates cation binding. The thermal denaturation temperature of E98Q was 3 degrees C higher than that of the wild-type enzyme in the absence of the cation, indicating that the removal of the unbalanced, buried charge of Glu98 stabilizes the enzyme. These results confirm that Glu98 is a crucial residue in the interaction of monovalent cations with FTHFS.
Asunto(s)
Cationes Monovalentes/química , Formiato-Tetrahidrofolato Ligasa/química , Ácido Aspártico/genética , Sitios de Unión/genética , Rastreo Diferencial de Calorimetría , Cesio/química , Clostridium/enzimología , Cristalografía por Rayos X , Estabilidad de Enzimas/genética , Formiato-Tetrahidrofolato Ligasa/genética , Formiato-Tetrahidrofolato Ligasa/aislamiento & purificación , Ácido Glutámico/genética , Glutamina/genética , Mutagénesis Sitio-Dirigida , Potasio/química , Desnaturalización Proteica , Compuestos de Amonio Cuaternario/química , TermodinámicaRESUMEN
The structure was solved at 2.5 A resolution using multiwavelength anomalous dispersion (MAD) scattering by Se-Met residues. The subunit of N(10)-formyltetrahydrofolate synthetase is composed of three domains organized around three mixed beta-sheets. There are two cavities between adjacent domains. One of them was identified as the nucleotide binding site by homology modeling. The large domain contains a seven-stranded beta-sheet surrounded by helices on both sides. The second domain contains a five-stranded beta-sheet with two alpha-helices packed on one side while the other two are a wall of the active site cavity. The third domain contains a four-stranded beta-sheet forming a half-barrel. The concave side is covered by two helices while the convex side is another wall of the large cavity. Arg 97 is likely involved in formyl phosphate binding. The tetrameric molecule is relatively flat with the shape of the letter X, and the active sites are located at the end of the subunits far from the subunit interface.
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Clostridium/enzimología , Formiato-Tetrahidrofolato Ligasa/química , Secuencia de Aminoácidos , Clostridium/química , Cristalización , Datos de Secuencia Molecular , Conformación Proteica , Alineación de SecuenciaRESUMEN
An RNA-dependent RNA polymerase denoted nonstructural protein 5B (NS5B) is the central enzyme in replication of the hepatitis C virus genome. Recent advances in the biochemical and structural understanding of NS5B include solubilization and purification of the full-length enzyme and various truncated forms. In vitro conditions for NS5B-catalyzed primer elongation using both homo- and heteropolymeric RNA templates were discovered. The crystal structure of the NS5B apoenzyme revealed a globular shape unique among polymerases, and implicated new structural features important for binding the RNA template and cognate ribonucleotide substrates. The crystallographic results also provided a structure-based framework for biochemical analyses and drug-design efforts. Finally, inhibitors of HCV RNA-dependent RNA polymerase have been reported.