The Stability of G6PD Is Affected by Mutations with Different Clinical Phenotypes
Por:
Gómez-Manzo S., Terrón-Hernández J., De la Mora-De la Mora I., González-Valdez A., Marcial-Quino J., García-Torres I., Vanoye-Carlo A., López-Velázquez G., Hernández-Alcántara G., Oria-Hernández J., Reyes-Vivas H., Enríquez-Flores S.
Publicada:
1 nov 2014
Resumen:
Glucose-6-phosphate dehydrogenase (G6PD) deficiency is the most common
enzyme deficiency worldwide, causing a wide spectrum of conditions with
severity classified from the mildest (Class IV) to the most severe
(Class I). To correlate mutation sites in the G6PD with the resulting
phenotypes, we studied four naturally occurring G6PD variants: Yucatan,
Nashville, Valladolid and Mexico City. For this purpose, we developed a
successful over-expression method that constitutes an easier and more
precise method for obtaining and characterizing these enzymes. The
k(cat) (catalytic constant) of all the studied variants was lower than
in the wild-type. The structural rigidity might be the cause and the
most evident consequence of the mutations is their impact on protein
stability and folding, as can be observed from the protein yield, the
T-50 (temperature where 50% of its original activity is retained)
values, and differences on hydrophobic regions. The mutations
corresponding to more severe phenotypes are related to the structural
NADP(+) region. This was clearly observed for the Classes III and II
variants, which became more thermostable with increasing NADP(+),
whereas the Class I variants remained thermolabile. The mutations
produce repulsive electric charges that, in the case of the Yucatan
variant, promote increased disorder of the C-terminus and consequently
affect the binding of NADP(+), leading to enzyme instability.
Filiaciones:
Gómez-Manzo S.:
Laboratorio de Bioquímica Genética, Instituto Nacional de Pediatría, México, D.F.04530, Mexico
Terrón-Hernández J.:
Laboratorio de Bioquímica Genética, Instituto Nacional de Pediatría, México, D.F.04530, Mexico
De la Mora-De la Mora I.:
Laboratorio de Bioquímica Genética, Instituto Nacional de Pediatría, México, D.F.04530, Mexico
González-Valdez A.:
Univ Nacl Autonoma Mexico, Dept Biol Mol & Biotecnol, Inst Invest Biomed, Mexico City 04510, DF, Mexico
Marcial-Quino J.:
Laboratorio de Bioquímica Genética, Instituto Nacional de Pediatría, México, D.F.04530, Mexico
García-Torres I.:
Laboratorio de Bioquímica Genética, Instituto Nacional de Pediatría, México, D.F.04530, Mexico
Vanoye-Carlo A.:
Laboratorio de Bioquímica Genética, Instituto Nacional de Pediatría, México, D.F.04530, Mexico
López-Velázquez G.:
Laboratorio de Bioquímica Genética, Instituto Nacional de Pediatría, México, D.F.04530, Mexico
Hernández-Alcántara G.:
Univ Nacl Autonoma Mexico, Fac Med, Dept Bioquim, Mexico City 04510, DF, Mexico
Oria-Hernández J.:
Laboratorio de Bioquímica Genética, Instituto Nacional de Pediatría, México, D.F.04530, Mexico
Reyes-Vivas H.:
Laboratorio de Bioquímica Genética, Instituto Nacional de Pediatría, México, D.F.04530, Mexico
Enríquez-Flores S.:
Laboratorio de Bioquímica Genética, Instituto Nacional de Pediatría, México, D.F.04530, Mexico
Gold
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