DevS, a heme-containing two-component oxygen sensor of Mycobacterium tuberculosis.
Mycobacterium tuberculosis can exist in the actively growing state of the overt disease or in a latent quiescent state that can be induced, among other things, by anaerobiosis. Eradication of the latent state is particularly difficult with the available drugs and requires prolonged treatment. DevS is a member of the DevS-DevR two-component regulatory system that is thought to mediate the cellular response to anaerobiosis. Here we report the cloning, expression, and initial characterization of a truncated version of DevS (DevS642) containing only the N-terminal GAF sensor domain (GAF-A) and of the full-length protein DevS. The DevS truncated construct quantitatively binds heme in a 1:1 stoichiometry, and the complex of the protein with ferrous heme reversibly binds O2, NO, and CO. UV-vis and resonance Raman spectroscopy of the wild-type protein and the H149A mutant confirm that His149 is the proximal ligand to the heme iron atom. While the heme-CO complex is present as two conformers in the GAF-A domain, a single set of [Fe-C-O] vibrations is observed with the full-length protein, suggesting that interactions between domains within DevS influence the distal pocket environment of the heme in the GAF-A domain.
Ioanoviciu
Alexandra
A
Department of Pharmaceutical Chemistry, University of California, 600 16th Street, San Francisco, California 94158-2517, USA.
Yukl
Erik T
ET
Moënne-Loccoz
Pierre
P
de Montellano
Paul R Ortiz
PR
D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000737:chemistry / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D002850:Chromatography, Gel; D003001:Cloning, Molecular; D004269:DNA, Bacterial / Q000235:genetics / Q000302:isolation & purification; D004591:Electrophoresis, Polyacrylamide Gel; D005798:Genes, Bacterial; D006420:Hemeproteins / Q000737:chemistry* / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D006639:Histidine / Q000737:chemistry; D006860:Hydrogen Bonding; D008024:Ligands; D008969:Molecular Sequence Data; D008970:Molecular Weight; D016296:Mutagenesis; D009154:Mutation; D009169:Mycobacterium tuberculosis / Q000235:genetics / Q000378:metabolism*; D021141:Nucleic Acid Amplification Techniques; D010100:Oxygen / Q000378:metabolism*; D011485:Protein Binding; D017434:Protein Structure, Tertiary; D013056:Spectrophotometry, Ultraviolet; D013059:Spectrum Analysis, Raman
D001426:Bacterial Proteins; D004269:DNA, Bacterial; D006420:Hemeproteins; D008024:Ligands; D006639:Histidine; D010100:Oxygen