The role of UbiX in Escherichia coli coenzyme Q biosynthesis

The reversible redox chemistry of coenzyme Q serves a crucial function in respiratory electron transport. Biosynthesis of Q in Escherichia coli depends on the ubi genes. However, very little is known about UbiX, an enzyme thought to be involved in the decarboxylation step in Q biosynthesis in E. col...

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Bibliographic Details
Published in:Archives of biochemistry and biophysics 2007-11, Vol.467 (2), p.144-153
Main Authors: Gulmezian, Melissa, Hyman, Kyle R., Marbois, Beth N., Clarke, Catherine F., Javor, George T.
Format: Article
Language:English
Subjects:
Carboxy-Lyases - metabolism
Cell Proliferation
Coenzyme Q biosynthesis
Decarboxylase
Escherichia coli
Escherichia coli - physiology
Escherichia coli Proteins - metabolism
Gene Expression Regulation, Bacterial - physiology
Gene Expression Regulation, Enzymologic - physiology
PAD1
Saccharomyces cerevisiae
ubiD
Ubiquinone
Ubiquinone - biosynthesis
ubiX
YDR538W
YDR539W
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Summary:The reversible redox chemistry of coenzyme Q serves a crucial function in respiratory electron transport. Biosynthesis of Q in Escherichia coli depends on the ubi genes. However, very little is known about UbiX, an enzyme thought to be involved in the decarboxylation step in Q biosynthesis in E. coli and Salmonella enterica. Here we characterize an E. coli ubiX gene deletion strain, LL1, to further elucidate E. coli ubiX function in Q biosynthesis. LLI produces very low levels of Q, grows slowly on succinate as the sole carbon source, accumulates 4-hydroxy-3-octaprenyl-benzoate, and has reduced UbiG O-methyltransferase activity. Expression of either E. coli ubiX or the Saccharomyces cerevisiae ortholog PAD1, rescues the deficient phenotypes of LL1, identifying PAD1 as an ortholog of ubiX. Our results suggest that both UbiX and UbiD are required for the decarboxylation of 4-hydroxy-3-octaprenyl-benzoate in E. coli coenzyme Q biosynthesis, especially during logarithmic growth.
ISSN:0003-9861
1096-0384
DOI:10.1016/j.abb.2007.08.009