title: ATP-dependent motor activity of the transcription termination factor Rho from Mycobacterium tuberculosis.
abstract: The bacterial transcription termination factor Rho-a ring-shaped molecular motor displaying directional, ATP-dependent RNA helicase/translocase activity-is an interesting therapeutic target. Recently, Rho from Mycobacterium tuberculosis (MtbRho) has been proposed to operate by a mechanism uncoupled from molecular motor action, suggesting that the manner used by Rho to dissociate transcriptional complexes is not conserved throughout the bacterial kingdom. Here, however, we demonstrate that MtbRho is a bona fide molecular motor and directional helicase which requires a catalytic site competent for ATP hydrolysis to disrupt RNA duplexes or transcription elongation complexes. Moreover, we show that idiosyncratic features of the MtbRho enzyme are conferred by a large, hydrophilic insertion in its N-terminal 'RNA binding' domain and by a non-canonical R-loop residue in its C-terminal 'motor' domain. We also show that the 'motor' domain of MtbRho has a low apparent affinity for the Rho inhibitor bicyclomycin, thereby contributing to explain why M. tuberculosis is resistant to this drug. Overall, our findings support that, in spite of adjustments of the Rho motor to specific traits of its hosting bacterium, the basic principles of Rho action are conserved across species and could thus constitute pertinent screening criteria in high-throughput searches of new Rho inhibitors.
authors.affiliation: Centre de Biophysique Moléculaire, CNRS UPR4301, rue Charles Sadron, 45071 Orléans cedex 2, France Ecole doctorale Santé, Sciences Biologiques et Chimie du Vivant (ED 549), Université d'Orléans, Orléans, France.
authors.forename: François
authors.initials: F
authors.lastname: D'Heygère
authors.affiliation: Centre de Biophysique Moléculaire, CNRS UPR4301, rue Charles Sadron, 45071 Orléans cedex 2, France.
authors.forename: Annie
authors.initials: A
authors.lastname: Schwartz
authors.affiliation: Centre de Biophysique Moléculaire, CNRS UPR4301, rue Charles Sadron, 45071 Orléans cedex 2, France.
authors.forename: Franck
authors.initials: F
authors.lastname: Coste
authors.affiliation: Centre de Biophysique Moléculaire, CNRS UPR4301, rue Charles Sadron, 45071 Orléans cedex 2, France ITP Sciences Biologiques & Chimie du Vivant, Université d'Orléans, Orléans, France.
authors.forename: Bertrand
authors.initials: B
authors.lastname: Castaing
authors.affiliation: Centre de Biophysique Moléculaire, CNRS UPR4301, rue Charles Sadron, 45071 Orléans cedex 2, France ITP Sciences Biologiques & Chimie du Vivant, Université d'Orléans, Orléans, France marc.boudvillain@cnrs-orleans.fr.
authors.forename: Marc
authors.identifier: http://orcid.org/0000-0002-6398-9122
authors.initials: M
authors.lastname: Boudvillain
mesh_terms: D000251:Adenosine Triphosphatases / Q000378:metabolism; D000255:Adenosine Triphosphate / Q000378:metabolism; D000494:Allosteric Regulation; D001426:Bacterial Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D050505:Mutant Proteins / Q000378:metabolism; D009169:Mycobacterium tuberculosis / Q000201:enzymology*; D020365:RNA Helicases / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D012330:RNA, Double-Stranded / Q000378:metabolism; D012234:Rho Factor / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D061806:Transcription Termination, Genetic
chemical_list: D001426:Bacterial Proteins; D050505:Mutant Proteins; D012330:RNA, Double-Stranded; D012234:Rho Factor; D000255:Adenosine Triphosphate; D000251:Adenosine Triphosphatases; D020365:RNA Helicases