title: A globin-coupled oxygen sensor from the facultatively alkaliphilic Bacillus halodurans C-125.
abstract: We have recently discovered heme-containing signal transducers from the archaeon Halobacterium salinarum (HemAT-Hs) and the gram-positive bacterium Bacillus subtilis (HemAT-Bs). These proteins bind diatomic oxygen and trigger aerotactic responses. We identified that HemAT oxygen-sensing domains contain a globin-coupled sensor (GCS) motif, which exists as a two-domain transducer, having no similarity to the PAS domain (Period circadian protein, Ah receptor nuclear translocator protein, Single-minded protein) superfamily transducers. Using the GCS motif, we predicted that a 439-amino-acid protein annotated as a methyl-accepting chemotaxis protein (MCP) in the facultatively alkaliphilic bacterium Bacillus halodurans is a globin-coupled oxygen sensor. We cloned, expressed, and purified GCS(Bh), and performed its spectral analysis. GCS(Bh), binds heme and shows myoglobin-like spectra. This suggests that GCS(Bh) acts as an oxygen sensor and transmits a conformational signal through a linked signaling domain to trigger an aerotactic response in B. halodurans.
authors.affiliation: Department of Microbiology, Snyder Hall 207, 2538 The Mall, University of Hawaii, Honolulu, Hawaii 96822, USA.
authors.forename: S
authors.initials: S
authors.lastname: Hou
authors.forename: C
authors.initials: C
authors.lastname: Belisle
authors.forename: S
authors.initials: S
authors.lastname: Lam
authors.forename: M
authors.initials: M
authors.lastname: Piatibratov
authors.forename: V
authors.initials: V
authors.lastname: Sivozhelezov
authors.forename: H
authors.initials: H
authors.lastname: Takami
authors.forename: M
authors.initials: M
authors.lastname: Alam
mesh_terms: D000595:Amino Acid Sequence; D001407:Bacillus / Q000235:genetics / Q000378:metabolism*; D001426:Bacterial Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D002352:Carrier Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D003001:Cloning, Molecular; D005914:Globins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D000081062:Heme-Binding Proteins; D006420:Hemeproteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D006863:Hydrogen-Ion Concentration; D008958:Models, Molecular; D008969:Molecular Sequence Data; D010100:Oxygen / Q000378:metabolism*; D017434:Protein Structure, Tertiary; D017386:Sequence Homology, Amino Acid
chemical_list: D001426:Bacterial Proteins; D002352:Carrier Proteins; D000081062:Heme-Binding Proteins; D006420:Hemeproteins; C454663:globin-coupled oxygen sensor protein, Bacillus halodurans; C404449:heme protein, bacteria; D005914:Globins; D010100:Oxygen