Conférence de Jean Luis RAMOS (EEZ-CSIC,Grenade, Espagne)
le mardi 17 février 2009 à 11 h, IBSM
(salle de conférences Jacques Senez), Campus Joseph Aiguier,
Bt IM, CNRS, Marseille : « One-component and two-component
regulatory systems promote solvent tolerance and degradation in
Pseudomonas ».
Résumé : Pseudomonas putida DOT-T1E is an extremely
solvent- and drug-resistant bacterium that is able to thrive in the
presence of toluene. Growth on toluene involves the degradation of
this compound via the TOD pathway, whose expression is driven by
the TodS/TodT two-component system. ITC studies have shown that
TodS binds toluene, creating a phosphorylation cascade that ends up
with TodT-P activating transcription from the promoter catabolic
gene operon. Thriving in toluene is energy-consuming and efflux
pumps play a key role in toluene tolerance. Two one-component
regulators, TtgR and TtgV, control the expression of the TtgABC and
TtgGHI efflux pumps. The mechanism of control will be discussed
based on the 3D structure of regulators bound to effectors. These
efflux pumps and regulators respond to antibiotics, dyes and
flavonoids in addition to solvents.