The role of UbiX in Escherichia coli coenzyme Q biosynthesis
Related Experiment Video
Updated: Jul 11, 2026

In Vitro Analysis of E3 Ubiquitin Ligase Function
Published on: May 14, 2021
Melissa Gulmezian1, Kyle R Hyman, Beth N Marbois
1Department of Chemistry and Biochemistry and The Molecular Biology Institute, University of California Los Angeles, 607 Charles E. Young Dr., Los Angeles, CA 90095-1569, USA.
Abstract:
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.
Related Concept Videos
Electron Transport Chain: Complex III and IV
Electron Transport Chain: Complex I and II
ROS generation is regulated and maintained at moderate levels necessary...
The Electron Transport Chain
Inhibitors of the electron transport chain
Rotenone, a widely used pesticide, prevents electron transfer from Fe-S cluster to ubiquinone or Q in...
Role of Reduced Coenzymes NADH and FADH₂
Electron Transport Chains
The ETC is comprised of...
Sulfur Assimilation

