A globin-coupled oxygen sensor from the facultatively alkaliphilic Bacillus halodurans C-125.
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.
Hou
S
S
Department of Microbiology, Snyder Hall 207, 2538 The Mall, University of Hawaii, Honolulu, Hawaii 96822, USA.
Belisle
C
C
Lam
S
S
Piatibratov
M
M
Sivozhelezov
V
V
Takami
H
H
Alam
M
M
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
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