Effect of mutation of proline 93 on redox unfolding/folding of bovine pancreatic ribonuclease A.
Biochemistry
; 40(29): 8536-41, 2001 Jul 24.
Article
en En
| MEDLINE
| ID: mdl-11456492
Both the reductive unfolding and oxidative regeneration of a P93A mutant and wild-type RNase A have been studied at 15 degrees C and pH 8.0. The rate of reduction of the 40--95 disulfide bond is accelerated about 120-fold by the P93A mutation, while the reduction of the 65--72 disulfide bond is not accelerated by this mutation (within the experimental error). Moreover, the reduction of native P93A to des[40--95] is about 10 times faster than the further reduction of the same des[40--95] species. These results demonstrate that the reduction of the mutant proceeds through a local unfolding event and provides strong support for our model in which the reduction of wild-type RNase A to the des species proceeds through two independent local conformational unfolding events. The oxidative regeneration rate of the P93A mutant is comparable to that of wild-type RNase A, suggesting that a cis 92--93 peptide group that is present in native wild-type RNase A and in native des[40--95], is not obligatory for the formation of the third (final) native disulfide bond of des[40--95] by reshuffling from an unstructured 3S precursor. Thus, the trans to cis isomerization of the Tyr92-Pro93 peptide group during the regeneration of wild-type RNase A may occur after the formation of the third native disulfide bond.
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Colección:
01-internacional
Base de datos:
MEDLINE
Asunto principal:
Ribonucleasa Pancreática
/
Prolina
/
Pliegue de Proteína
/
Mutación Puntual
Límite:
Animals
Idioma:
En
Revista:
Biochemistry
Año:
2001
Tipo del documento:
Article
País de afiliación:
Estados Unidos
Pais de publicación:
Estados Unidos