UbiB proteins mediate an ATP ‐dependent decarboxylation step in bacterial ubiquinone biosynthesis
Abstract
Polyisoprenoid quinones such as ubiquinone (UQ) play an essential role in cellular physiology, acting as membrane‐bound electron and proton carriers in respiratory chains and other biological processes across all domains of life. In Escherichia coli , the canonical UQ biosynthesis pathway is well characterized. It involves 12 proteins (UbiA–UbiK and UbiX), most of which catalyze one of the eight modifications of the aromatic ring derived from 4‐hydroxybenzoic acid (4‐HB), while others (UbiB, UbiJ, UbiK) act as accessory factors ensuring efficient UQ production. Following prenylation by UbiA and subsequent decarboxylation by the UbiX/UbiD system, the final six reactions are catalyzed within a soluble Ubi‐complex. UbiB, an atypical protein kinase‐like enzyme, was proposed to extract decarboxylated intermediates from the membrane and mediate their delivery to the Ubi‐complex. In this study, we demonstrate the existence of an alternative decarboxylation system in E. coli , as UQ biosynthesis can proceed in the absence of the UbiX/UbiD system. Our results show that this alternative decarboxylation activity depends on UbiB and requires its adenosine triphosphatase activity. Bioinformatic analyses further revealed that approximately 27% of Pseudomonadota species lack UbiX/UbiD homologs, and we found that UbiB proteins from two such species enhance the alternative decarboxylation activity when expressed in E. coli . In addition, we identified conserved residues in UbiB that are specifically required for decarboxylation but dispensable for the delivery of UQ intermediates to the Ubi‐complex. Taken together, our findings support a model in which UbiB acts as an ATP‐dependent decarboxylase, thereby broadening the functional scope of this poorly characterized protein.
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BibTeX
@article{kazemzadeh2026ubib,
title = {{UbiB proteins mediate an ATP ‐dependent decarboxylation step in bacterial ubiquinone biosynthesis}},
author = {Katayoun Kazemzadeh and Bruno Faivre and Sophie-Carole Chobert and Martial Rey and Sophie Abby and Julie Michaud and Tuan-Anh Dinh and Alexandre Chilin and Olivier Lerouxel and Marc Fontecave and Fabien Pierrel and Murielle Lombard and Ludovic Pelosi},
journal = {FEBS Journal},
year = {2026},
month = oct,
doi = {10.1111/febs.70749},
url = {https://hal.science/hal-05828816v1},
note = {CC BY-NC-SA 4.0},
}
RIS
TY - JOUR
TI - UbiB proteins mediate an ATP ‐dependent decarboxylation step in bacterial ubiquinone biosynthesis
AU - Katayoun Kazemzadeh
AU - Bruno Faivre
AU - Sophie-Carole Chobert
AU - Martial Rey
AU - Sophie Abby
AU - Julie Michaud
AU - Tuan-Anh Dinh
AU - Alexandre Chilin
AU - Olivier Lerouxel
AU - Marc Fontecave
AU - Fabien Pierrel
AU - Murielle Lombard
AU - Ludovic Pelosi
PY - 2026
DA - 2026/10/01
JO - FEBS Journal
DO - 10.1111/febs.70749
UR - https://hal.science/hal-05828816v1
AB - Polyisoprenoid quinones such as ubiquinone (UQ) play an essential role in cellular physiology, acting as membrane‐bound electron and proton carriers in respiratory chains and other biological processes across all domains of life. In Escherichia coli , the canonical UQ biosynthesis pathway is well characterized. It involves 12 proteins (UbiA–UbiK and UbiX), most of which catalyze one of the eight modifications of the aromatic ring derived from 4‐hydroxybenzoic acid (4‐HB), while others (UbiB, UbiJ, UbiK) act as accessory factors ensuring efficient UQ production. Following prenylation by UbiA and subsequent decarboxylation by the UbiX/UbiD system, the final six reactions are catalyzed within a soluble Ubi‐complex. UbiB, an atypical protein kinase‐like enzyme, was proposed to extract decarboxylated intermediates from the membrane and mediate their delivery to the Ubi‐complex. In this study, we demonstrate the existence of an alternative decarboxylation system in E. coli , as UQ biosynthesis can proceed in the absence of the UbiX/UbiD system. Our results show that this alternative decarboxylation activity depends on UbiB and requires its adenosine triphosphatase activity. Bioinformatic analyses further revealed that approximately 27% of Pseudomonadota species lack UbiX/UbiD homologs, and we found that UbiB proteins from two such species enhance the alternative decarboxylation activity when expressed in E. coli . In addition, we identified conserved residues in UbiB that are specifically required for decarboxylation but dispensable for the delivery of UQ intermediates to the Ubi‐complex. Taken together, our findings support a model in which UbiB acts as an ATP‐dependent decarboxylase, thereby broadening the functional scope of this poorly characterized protein.
SN - 1742-464X
SN - 1742-4658
ER -