Cryo-EM structure of transcription termination factor Rho from Mycobacterium tuberculosis reveals bicyclomycin resistance mechanism


Scientific Field Life & Health Sciences

Fellow Dr Emmanuel Saridakis
Commun Biol 5, 120 (2022)

Saridakis Emmanuel1, 2, 5, Vishwakarma Rishi3, 6, Lai-Kee-Him Josephine3, Martin Kevin3, Simon Isabelle4, 5, Cohen-Gonsaud Martin3, Coste Franck5, Bron Patrick3, Margeat Emmanuel3, Boudvillain Marc1, 5

1LE STUDIUM Institute for Advanced Studies, 45000 Orléans, France

2Institute of Nanoscience and Nanotechnology, NCSR “Demokritos”, Ag. Paraskevi, 15310, Athens, Greece

3CBS (Centre de Biologie Structurale), Univ Montpellier, CNRS, INSERM, Montpellier, France

4ED 549, Santé, Sciences Biologiques & Chimie du Vivant, Université d’Orléans, Orléans, France

5Centre de Biophysique Moléculaire, CNRS UPR4301, rue Charles Sadron, affiliated with Université d’Orléans, 45071, Orléans, cedex 2, France

6Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, State College, PA, 16802, USA


The bacterial Rho factor is a ring-shaped motor triggering genome-wide transcription termination and R-loop dissociation. Rho is essential in many species, including in Mycobacterium tuberculosis where rho gene inactivation leads to rapid death. Yet, the M. tuberculosis Rho [MtbRho] factor displays poor NTPase and helicase activities, and resistance to the natural Rho inhibitor bicyclomycin [BCM] that remain unexplained. To address these issues, we solved the cryo-EM structure of MtbRho at 3.3 Å resolution. The MtbRho hexamer is poised into a pre-catalytic, open-ring state wherein specific contacts stabilize ATP in intersubunit ATPase pockets, thereby explaining the cofactor preference of MtbRho. We reveal a leucine-to-methionine substitution that creates a steric bulk in BCM binding cavities near the positions of ATP γ-phosphates, and confers resistance to BCM at the expense of motor efficiency. Our work contributes to explain the unusual features of MtbRho and provides a framework for future antibiotic development.

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Commun Biol