Ubiquinone is an essential cofactor in bioenergetics. Yet its biosynthesis is still poorly understood, despite the fact that it represents a real chemical challenge due to its structural complexity and water insolubility. For several years, we have been interested in the multiprotein and multienzyme complex involved in ubiquinone biosynthesis. Most recently, we have contributed to several major advances in this field: (i) on the one hand, we have demonstrated that this biosynthesis is carried out within a fully characterized soluble multiprotein complex (U1); (ii) we have discovered new protein players involved in anaerobic ubiquinone biosynthesis (U2); (iii) we have discovered the anaerobic ubiquinone biosynthetic system, which raises novel questions concerning biological hydroxylation reactions in the absence of oxygen.
