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H-NOX from Clostridium botulinum, like H-NOX from Thermoanaerobacter tengcongensis, Binds Oxygen but with a Less Stable Oxyferrous Heme Intermediate.

ABSTRACT: Heme nitric oxide/oxygen binding protein isolated from the obligate anaerobe Clostridium botulinum (Cb H-NOX) was previously reported to bind NO with a femtomolar K(D) (Nioche, P. et al. Science 2004, 306, 1550-1553). On the other hand, no oxyferrous Cb H-NOX was observed despite full conservation of the key residues that stabilize the oxyferrous complex in the H-NOX from Thermoanaerobacter tengcongensis (Tt H-NOX) (the same study). In this study, we re-measured the kinetics/affinities of Cb H-NOX for CO, NO, and O2. K(D)(CO) for the simple one-step equilibrium binding was 1.6 × 10(-7) M. The K(D)(NO) of Cb H-NOX was 8.0 × 10(-11) M for the first six-coordinate NO complex, and the previous femtomolar K(D)(NO) was actually an apparent K(D) for its multiple-step NO binding. An oxyferrous Cb H-NOX was clearly observed with a K(D)(O2) of 5.3 × 10(-5) M, which is significantly higher than Tt H-NOX's K(D)(O2) = 4.4 × 10(-8) M. The gaseous ligand binding of Cb H-NOX provides another supportive example for the "sliding scale rule" hypothesis (Tsai, A.-L. et al. Antioxid. Redox Signal. 2012, 17, 1246-1263), and the presence of hydrogen bond donor Tyr139 in Cb H-NOX selectively enhanced its affinity for oxygen.

SUBMITTER: Wu G

PROVIDER: S-EPMC8344375 | biostudies-literature |

REPOSITORIES: biostudies-literature

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Thermal stability of glucokinases in Thermoanaerobacter tengcongensis.

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Project description:Comprehensive and quantitative information of the thermophile proteome is an important source for understanding of the survival mechanism under high growth temperature. Thermoanaerobacter tengcongensis (T. tengcongensis), a typical anaerobic thermophilic eubacterium, was selected to quantitatively evaluate its protein abundance changes in response to four different temperatures. Thermoanaerobacter tengcongensis proteins were trypsine digested, separated with high-pH RP, and identified with MS/MS analysis. The raw MS/MS data were converted into MGF format by Proteome Discoverer 1.2 (Thermo Fisher Scientific, Waltham, MA, USA). And the exported MGF files were searched by Mascot 2.3.02 (Matrix Science, Boston, MA, USA) against the database with all 2588 predicted proteins in T. tengcongensis downloaded from NCBI (NCBI reference sequence: NC_003869.1). An automatic decoy database search was performed. Several parameters in Mascot were set for peptide searching, tolerance of one missed cleavage of trypsin, Carbamidomethyl (C),iTRAQ8plex (K) and iTRAQ8plex (N-term) as fixed modification, iTRAQ8plex (Y),Oxidation (M) as variable modification. The precursor mass tolerance was 10 ppm, and the product ion tolerance was 0.02 Da.

2013-08-13 | PXD000264 | Pride

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2014-03-30 | PXD000864 | Pride

Thermostable lipases from the extreme thermophilic anaerobic bacteria Thermoanaerobacter thermohydrosulfuricus SOL1 and Caldanaerobacter subterraneus subsp. tengcongensis.

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Dimeric structure of the N-terminal domain of PriB protein from Thermoanaerobacter tengcongensis solved ab initio.

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| S-EPMC3498933 | biostudies-literature

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