Molecular characterization of a novel His333Arg variant of human protoporphyrinogen oxidase IX.
Biochem Biophys Res Commun
; 588: 182-186, 2022 01 15.
Article
en En
| MEDLINE
| ID: mdl-34968794
ABSTRACT
Variegate porphyria is caused by mutations in the protoporphyrinogen oxidase IX (PPOX, EC 1.3.3.4) gene, resulting in reduced overall enzymatic activity of PPOX in human tissues. Recently, we have identified the His333Arg mutation in the PPOX protein (PPOX(H333R)) as a putative founder mutation in the Moroccan Jewish population. Herein we report the molecular characterization of PPOX(H333R) in vitro and in cells. Purified recombinant PPOX(H333R) did not show any appreciable enzymatic activity in vitro, corroborating the clinical findings. Biophysical experiments and molecular modeling revealed that PPOX(H333R) is not folded properly and fails to adopt its native functional three-dimensional conformation due to steric clashes in the vicinity of the active site of the enzyme. On the other hand, PPOX(H333R) subcellular distribution, as evaluated by live-cell confocal microscopy, is unimpaired suggesting that the functional three-dimensional fold is not required for efficient transport of the polypeptide chain into mitochondria. Overall, the data presented here provide molecular underpinnings of the pathogenicity of PPOX(H333R) and might serve as a blueprint for deciphering whether a given PPOX variant represents a disease-causing mutation.
Palabras clave
Texto completo:
1
Colección:
01-internacional
Banco de datos:
MEDLINE
Asunto principal:
Proteínas Mitocondriales
/
Protoporfirinógeno-Oxidasa
/
Flavoproteínas
/
Mutación
Tipo de estudio:
Prognostic_studies
Límite:
Humans
Idioma:
En
Revista:
Biochem Biophys Res Commun
Año:
2022
Tipo del documento:
Article