The Saccharomyces cerevisiae COQ6 gene encodes a mitochondrial flavin-dependent monooxygenase required for coenzyme Q biosynthesis.
Coenzyme Q (Q) is a lipid that functions as an electron carrier in the mitochondrial respiratory chain in eukaryotes. There are eight complementation groups of Q-deficient Saccharomyces cerevisiae mutants, designated coq1-coq8. Here we have isolated the COQ6 gene by functional complementation and, in contrast to a previous report, find it is not an essential gene. coq6 mutants are unable to grow on nonfermentable carbon sources and do not synthesize Q but instead accumulate the Q biosynthetic intermediate 3-hexaprenyl-4-hydroxybenzoic acid. The Coq6 polypeptide is imported into the mitochondria in a membrane potential-dependent manner. Coq6p is a peripheral membrane protein that localizes to the matrix side of the inner mitochondrial membrane. Based on sequence homology to known proteins, we suggest that COQ6 encodes a flavin-dependent monooxygenase required for one or more steps in Q biosynthesis.
Gin
Peter
P
Department of Chemistry and Biochemistry and the Molecular Biology Institute, University of California, Los Angeles, California 90095, USA.
Hsu
Adam Y
AY
Rothman
Steven C
SC
Jonassen
Tanya
T
Lee
Peter T
PT
Tzagoloff
Alexander
A
Clarke
Catherine F
CF
D020816:Amino Acid Motifs; D000595:Amino Acid Sequence; D002244:Carbon / Q000378:metabolism; D002455:Cell Division; D002851:Chromatography, High Pressure Liquid; D003001:Cloning, Molecular; D004926:Escherichia coli / Q000378:metabolism; D005415:Flavins / Q000378:metabolism; D017353:Gene Deletion; D005816:Genetic Complementation Test; D005838:Genotype; D062385:Hydroxybenzoates / Q000378:metabolism; D015151:Immunoblotting; D008564:Membrane Potentials; D008928:Mitochondria / Q000378:metabolism; D006899:Mixed Function Oxygenases / Q000737:chemistry* / Q000378:metabolism; D008956:Models, Chemical; D008957:Models, Genetic; D008969:Molecular Sequence Data; D009154:Mutation; D010957:Plasmids / Q000378:metabolism; D011485:Protein Binding; D012441:Saccharomyces cerevisiae / Q000201:enzymology / Q000235:genetics*; D017386:Sequence Homology, Amino Acid; D014315:Triterpenes / Q000378:metabolism; D014451:Ubiquinone / Q000096:biosynthesis* / Q000235:genetics*
D005415:Flavins; D062385:Hydroxybenzoates; D014315:Triterpenes; C032165:ubiquinone 6; D014451:Ubiquinone; C094743:3-hexaprenyl-4-hydroxybenzoic acid; D002244:Carbon; D006899:Mixed Function Oxygenases