Ubiquinone (coenzyme Q) biosynthesis in bacteria is a vital metabolic pathway responsible for producing ubiquinone, a lipid-soluble molecule that plays a central role in the electron transport chain (ETC) and cellular respiration. The process begins with the precursor 4-hydroxybenzoate (4-HB), which is derived from tyrosine or chorismate. Through a series of enzymatic reactions, a polyprenyl side chain is attached to 4-HB by 4-hydroxybenzoate polyprenyltransferase to form 4-hydroxy-3-polyprenylbenzoate, which is subsequently modified by hydroxylation, methylation, and decarboxylation steps. These modifications involve key enzymes such as monooxygenases and methyltransferases, leading to the production of ubiquinone. The length of the polyprenyl side chain varies among species and is determined by specific polyprenyl synthases. Ubiquinone acts as a mobile electron carrier within the bacterial membrane, shuttling electrons between complexes in the ETC and contributing to the generation of a proton gradient used for ATP synthesis. This pathway is essential for energy metabolism in aerobic bacteria, and disruptions can severely impair cellular respiration. Furthermore, ubiquinone also functions as an antioxidant, protecting bacterial cells from oxidative damage, underscoring its dual importance in bioenergetics and stress defense.

Ubiquinone biosynthesis References