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Mitochondrial targeting of human protoporphyrinogen oxidase
Author(s) -
Davids Lester M.,
Corrigall Anne V.,
Meissner Peter N.
Publication year - 2006
Publication title -
cell biology international
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.932
H-Index - 77
eISSN - 1095-8355
pISSN - 1065-6995
DOI - 10.1016/j.cellbi.2006.02.001
Subject(s) - protoporphyrinogen oxidase , mitochondrion , inner mitochondrial membrane , heme , biochemistry , fusion protein , chemistry , biology , microbiology and biotechnology , enzyme , recombinant dna , gene
Variegate porphyria is an autosomal dominant disorder of heme metabolism resulting from a deficiency in protoporphyrinogen oxidase, an enzyme located on the inner mitochondrial membrane. This study examined the effect of three South African VP‐causing mutations (H20P, R59W, R168C) on mitochondrial targeting. Only H20P did not target, and of eight protoporphyrinogen oxidase—GFP chimeric fusion proteins created, N‐terminal residues 1–17 were found to be the minimal protoporphyrinogen oxidase sequence required for efficient mitochondrial targeting. Removal of this N‐terminal sequence displayed mitochondrial localization, suggesting internal mitochondrial targeting signals. In addition, six constructs were engineered to assess the effect of charge and helicity on mitochondrial targeting of the protein. Of those engineered, only the PPOX20/H20P‐GFP construct abolished mitochondrial targeting, presumably through disruption of the protoporphyrinogen oxidase α‐helix. Based on our results we propose a mechanism for protoporphyrinogen oxidase targeting to the mitochondrion.