Oxygen-sensing mechanism of HemAT from Bacillus subtilis: a resonance Raman spectroscopic study.
Resonance Raman (RR) evidence for structural linkage between the distal side of heme pocket and the signaling domain of an oxygen sensing hemoprotein, HemAT-Bs, is reported. The band-fitting analyses of the RR spectra in the Fe-O2 stretching (nuFe-O2) region revealed the presence of three conformers with nuFe-O2 at 554, 566, and 572 cm-1, which reflect different H-bond strengths on the bound O2 molecule. While recent X-ray analysis for CN--bound HemAT-Bs suggested the importance of Thr95 and Tyr70, the species with the strongest H-bond (554 cm-1) was deleted in the T95A mutant and also by removal of the linker and signal domains; however, the Y70F mutant maintained the same three conformers. A scheme for specific O2 sensing and signaling mechanism is discussed.
Ohta
Takehiro
T
Okazaki Institute for Integrative Bioscience, National Institutes of Natural Sciences, Okazaki, Aichi 444-8787, Japan.
Yoshimura
Hideaki
H
Yoshioka
Shiro
S
Aono
Shigetoshi
S
Kitagawa
Teizo
T
D001412:Bacillus subtilis / Q000737:chemistry / Q000378:metabolism; D001426:Bacterial Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D000081062:Heme-Binding Proteins; D006420:Hemeproteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D016296:Mutagenesis; D010100:Oxygen / Q000032:analysis* / Q000378:metabolism; D010103:Oxygen Isotopes; D011487:Protein Conformation; D017434:Protein Structure, Tertiary; D013059:Spectrum Analysis, Raman
D001426:Bacterial Proteins; D000081062:Heme-Binding Proteins; D006420:Hemeproteins; D010103:Oxygen Isotopes; C404449:heme protein, bacteria; D010100:Oxygen