Back to Search
Start Over
Yeast Coq9 controls deamination of coenzyme Q intermediates that derive from para-aminobenzoic acid
- Source :
- Biochimica et biophysica acta, vol 1851, iss 9
- Publication Year :
- 2015
- Publisher :
- Elsevier BV, 2015.
-
Abstract
- Coq9 is a polypeptide subunit in a mitochondrial multi-subunit complex, termed the CoQ-synthome, required for biosynthesis of coenzyme Q (ubiquinone or Q). Deletion of COQ9 results in dissociation of the CoQ-synthome, but over-expression of Coq8 putative kinase stabilizes the CoQ-synthome in the coq9 null mutant and leads to the accumulation of two nitrogen-containing Q intermediates, imino-demethoxy-Q6 (IDMQ6) and 3-hexaprenyl-4-aminophenol (4-AP) when para-aminobenzoic acid (pABA) is provided as a ring precursor. To investigate whether Coq9 is responsible for deamination steps in Q biosynthesis, we utilized the yeast coq5-5 point mutant. The yeast coq5-5 point mutant is defective in the C-methyltransferase step of Q biosynthesis but retains normal steady-state levels of the Coq5 polypeptide. Here, we show that when high amounts of 13C6-pABA are provided, the coq5-5 mutant accumulates both 13C6-imino-demethyl-demethoxy-Q6 (13C6-IDDMQ6) and 13C6-demethyl-demethoxy-Q6 (13C6-DDMQ6). Deletion of COQ9 in the yeast coq5-5 mutant along with Coq8 over-expression and 13C6- pABA labeling leads to the absence of 13C6-DDMQ6, and the nitrogen-containing intermediates 13C6-4-AP and 13C6-IDDMQ6 persist. We describe a coq9 temperature-sensitive mutant and show that at the non-permissive temperature, steady-state polypeptide levels of Coq9-ts19 increased, while Coq4, Coq5, Coq6, and Coq7 decreased. The coq9-ts19 mutant had decreased Q6 content and increased levels of nitrogen-containing intermediates. These findings identify Coq9 as a multi-functional protein that is required for the function of Coq6 and Coq7 hydroxylases, for removal of the nitrogen substituent from pABA-derived Q intermediates, and is an essential component of the CoQ synthome.
- Subjects :
- Models, Molecular
Temperature-sensitive mutant
Saccharomyces cerevisiae Proteins
Ubiquinone
Saccharomyces cerevisiae
Mutant
Deamination
Article
Mitochondrial Proteins
chemistry.chemical_compound
Biosynthesis
Models
Gene Expression Regulation, Fungal
Genetics
COQ7
Point Mutation
Molecular Biology
Mass spectrometry
biology
Q biosynthetic intermediates
Temperature
Molecular
Coenzyme Q
Methyltransferases
Cell Biology
Biological Sciences
biology.organism_classification
Yeast
Fungal
Gene Expression Regulation
Biochemistry
chemistry
Mitochondrial metabolism
Coenzyme Q – cytochrome c reductase
Physical Sciences
4-Aminobenzoic Acid
Signal Transduction
Subjects
Details
- ISSN :
- 13881981
- Volume :
- 1851
- Database :
- OpenAIRE
- Journal :
- Biochimica et Biophysica Acta (BBA) - Molecular and Cell Biology of Lipids
- Accession number :
- edsair.doi.dedup.....5e5b09465048c0d61c703ad59e4d38b6