Mycobacterium tuberculosis DosS binds H2S through its Fe3+ heme iron to regulate the DosR dormancy regulon
Ritesh R. Sevalkar,
Joel N. Glasgow,
Martín Pettinati,
Marcelo A. Marti,
Vineel P. Reddy,
Swati Basu,
Elmira Alipour,
Daniel B. Kim-Shapiro,
Dario A. Estrin,
Jack R. Lancaster, Jr.,
Adrie J.C. Steyn
Affiliations
Ritesh R. Sevalkar
Department of Microbiology, University of Alabama at Birmingham, Birmingham, AL, USA
Joel N. Glasgow
Department of Microbiology, University of Alabama at Birmingham, Birmingham, AL, USA; Corresponding author. University of Alabama at Birmingham, USA.
Martín Pettinati
Universidad de Buenos Aires, Facultad de Ciencias Exactas y Naturales, Departamento de Química Inorgánica, Analítica y Química Física, Buenos Aires, Argentina; CONICET-Universidad de Buenos Aires, Instituto de Química Física de los Materiales, Medio Ambiente y Energía (INQUIMAE), Buenos Aires, Argentina
Marcelo A. Marti
Universidad de Buenos Aires, Facultad de Ciencias Exactas y Naturales, Departamento de Química Biológica, Buenos Aires, Argentina; CONICET-Universidad de Buenos Aires, Instituto de Química Biológica (IQUIBICEN), Buenos Aires, Argentina
Vineel P. Reddy
Department of Microbiology, University of Alabama at Birmingham, Birmingham, AL, USA
Swati Basu
Department of Physics, Wake Forest University, Winston-Salem, NC, USA
Elmira Alipour
Department of Physics, Wake Forest University, Winston-Salem, NC, USA
Daniel B. Kim-Shapiro
Department of Physics, Wake Forest University, Winston-Salem, NC, USA
Dario A. Estrin
Universidad de Buenos Aires, Facultad de Ciencias Exactas y Naturales, Departamento de Química Inorgánica, Analítica y Química Física, Buenos Aires, Argentina; CONICET-Universidad de Buenos Aires, Instituto de Química Física de los Materiales, Medio Ambiente y Energía (INQUIMAE), Buenos Aires, Argentina
Jack R. Lancaster, Jr.
Department of Pharmacology & Chemical Biology, Vascular Medicine Institute, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA
Adrie J.C. Steyn
Department of Microbiology, University of Alabama at Birmingham, Birmingham, AL, USA; Centers for AIDS Research and Free Radical Biology, University of Alabama at Birmingham, Birmingham, AL, USA; Africa Health Research Institute, University of KwaZulu-Natal, Durban, South Africa; Corresponding author. Department of Microbiology, and Centers for AIDS Research and Free Radical Biology, University of Alabama at Birmingham, Birmingham, AL, USA.
Mycobacterium tuberculosis (Mtb) senses and responds to host-derived gasotransmitters NO and CO via heme-containing sensor kinases DosS and DosT and the response regulator DosR. Hydrogen sulfide (H2S) is an important signaling molecule in mammals, but its role in Mtb physiology is unclear. We have previously shown that exogenous H2S can modulate expression of genes in the Dos dormancy regulon via an unknown mechanism(s). Here, we test the hypothesis that Mtb senses and responds to H2S via the DosS/T/R system. Using UV–Vis and EPR spectroscopy, we show that H2S binds directly to the ferric (Fe3+) heme of DosS (KDapp = 5.30 μM) but not the ferrous (Fe2+) form. No interaction with DosT(Fe2+-O2) was detected. We found that the binding of sulfide can slowly reduce the DosS heme iron to the ferrous form. Steered Molecular Dynamics simulations show that H2S, and not the charged HS− species, can enter the DosS heme pocket. We also show that H2S increases DosS autokinase activity and subsequent phosphorylation of DosR, and H2S-mediated increases in Dos regulon gene expression is lost in Mtb lacking DosS. Finally, we demonstrate that physiological levels of H2S in macrophages can induce DosR regulon genes via DosS. Overall, these data reveal a novel mechanism whereby Mtb senses and responds to a third host gasotransmitter, H2S, via DosS(Fe3+). These findings highlight the remarkable plasticity of DosS and establish a new paradigm for how bacteria can sense multiple gasotransmitters through a single heme sensor kinase.