Contributors: Adaptation au stress et Métabolisme chez les entérobactéries - Stress adaptation and metabolism in enterobacteria (SAMe); Université Paris Cité (UPCité)-Microbiologie Intégrative et Moléculaire (UMR6047); Institut Pasteur Paris (IP)-Centre National de la Recherche Scientifique (CNRS)-Institut Pasteur Paris (IP)-Centre National de la Recherche Scientifique (CNRS); Translational microbial Evolution and Engineering (TIMC-TrEE); Translational Innovation in Medicine and Complexity / Recherche Translationnelle et Innovation en Médecine et Complexité - UMR 5525 (TIMC ); VetAgro Sup - Institut national d'enseignement supérieur et de recherche en alimentation, santé animale, sciences agronomiques et de l'environnement (VAS)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP ); Université Grenoble Alpes (UGA)-VetAgro Sup - Institut national d'enseignement supérieur et de recherche en alimentation, santé animale, sciences agronomiques et de l'environnement (VAS)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP ); Université Grenoble Alpes (UGA); Institute for Advanced Biosciences / Institut pour l'Avancée des Biosciences (Grenoble) (IAB); Centre Hospitalier Universitaire CHU Grenoble (CHUGA)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Etablissement français du sang - Auvergne-Rhône-Alpes (EFS)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA); This project was supported by Institut Pasteur and CNRS and by grants from the ANR (ANR-10-LABX-62-IBEID and ANR-19-CE44-0014O2-TABOO).; ANR-10-LABX-0062,IBEID,Integrative Biology of Emerging Infectious Diseases(2010); ANR-19-CE44-0014,O2-taboo,hydroxylation indépendante d'O2 et synthèse anaérobie d'ubiquinone(2019)
نبذة مختصرة : Isoprenoid quinones are essential for cellular physiology. They act as electron and proton shuttles in respiratory chains and in various biological processes. Escherichia coli and many α, β, and γ proteobacteria possess two types of isoprenoid quinones: ubiquinone (UQ) is mainly used under aerobiosis, while (demethyl)menaquinones ((D)MK) are mostly used under anaerobiosis. Yet, we recently established the existence of an anaerobic O 2 - independent UQ biosynthesis pathway controlled by ubiT, ubiU, and ubiV genes. Here, we characterize the regulation of ubiTUV genes in E. coli. We show that the three genes are transcribed as two divergent operons that are both under the control of the O 2 sensing Fnr transcriptional regulator. Phenotypic analyses using a menA mutant devoid of (D)MK revealed that UbiUV-dependent UQ synthesis is essential for nitrate respiration and for uracil biosynthesis under anaerobiosis, while it contributes, though modestly, to bacterial multiplication in the mouse gut. Moreover, we showed by genetic study and 18 O 2 labelling that UbiUV contribute to hydroxylation of ubiquinone precursors through a unique O 2 - independent process. Last, we report a crucial role of ubiT in allowing E. coli to shift efficiently from anaerobic to aerobic conditions. Overall, this study uncovers a new facet of the strategy used by E. coli to adjust its metabolism upon changing O 2 levels and respiratory conditions. This work links respiratory mechanisms to phenotypic adaptation, a major driver in the capacity of E. coli to multiply in gut microbiota, and of facultative anaerobic pathogens to multiply in their host. ABSTRACT IMPORTANCE Enterobacteria multiplication in the gastrointestinal tract is linked to microaerobic respiration and associated to various inflammatory bowel diseases. Our study focuses on biosynthesis of ubiquinone (UQ), a key player in respiratory chains, under anaerobiosis. The importance of this study stems from the fact that UQ usage was for long considered to be restricted to aerobic ...
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