PMID:10485293
| Citation |
Narita, S, Taketani, S and Inokuchi, H (1999) Oxidation of protoporphyrinogen IX in Escherichia coli is mediated by the aerobic coproporphyrinogen oxidase. Mol. Gen. Genet. 261:1012-20 |
|---|---|
| Abstract |
Protoporphyrinogen oxidase, the penultimate enzyme involved in the biosynthetic pathway for heme, catalyzes the removal of six electrons from protoporphyrinogen IX to generate protoporphyrin IX. In Escherichia coli, this enzyme is encoded by the hemG gene. In this study we examined possible alternate pathways for the oxidation of protoporphyrinogen IX to protoporphyrin IX, by isolating and investigating E. coli mutants that can still grow normally when the hemG gene is disrupted. One of these mutants was characterized in detail and had a mutation in the promoter region of the hemF gene, which encodes aerobic coproporphyrinogen oxidase, the enzyme involved in the step immediately before protoporphyrinogen oxidase. Measurement of the promoter activity of the hemF gene showed that the level of transcription was elevated by the mutation. Overexpression of a wild-type hemF gene cloned in a multicopy plasmid also restored the growth of deltahemG strain. Extracts from cells that overexpress hemF exhibited an increased ability to oxidize protoporphyrinogen IX to protoporphyrin IX. These findings suggest that the E. coli aerobic coproporphyrinogen oxidase has an intrinsic capacity to oxidize not only coproporphyrinogen III but also protoporphyrinogen IX. |
| Links | |
| Keywords |
Base Sequence; Cloning, Molecular; Coproporphyrinogen Oxidase/genetics; Coproporphyrinogen Oxidase/metabolism; DNA, Bacterial; Escherichia coli/metabolism; Escherichia coli Proteins; Mutagenesis; Oxidation-Reduction; Phenotype; Protoporphyrinogen Oxidase; Protoporphyrins/metabolism; Recombinant Proteins/genetics; Recombinant Proteins/metabolism |
| edit table |
Significance
You can help EcoliWiki by summarizing why this paper is useful
Useful Materials and Methods
You can help Ecoliwiki by describing the useful materials (strains, plasmids, antibodies, etc) described in this paper.
Annotations
<annotationlinks/>
EcoliWiki Links
Add links to pages that link here (e.g. gene, product, method pages)
References
See Help:References for how to manage references in EcoliWiki.