CooA, a paradigm for gas sensing regulatory proteins

Roberts, Gary P.; Kerby, Robert L.; Youn, Hwan; Conrad, Mary

doi:10.1016/j.jinorgbio.2004.10.032

Cited by 88 publications

(82 citation statements)

References 95 publications

(133 reference statements)

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“…The best known CO-sensors is CooA, a homodimeric heme-containing protein, which regulates the CO oxidation system in the photosynthetic bacterium Rodospirillum rubrum [59][60][61][62], and the mammalian neuronal (N) period circadian protein (Per)-aryl hydrocarbon receptor nuclear translocator protein (Arnt) -single-minded protein (Sim) protein 2 (NPAS2), a member of the bHLH family of transcription factors expressed in the forebrain, which is a CO-dependent regulator of the circadian rhythm [59,60,63].…”

Section: Co Sensingmentioning

confidence: 99%

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CO metabolism, sensing, and signaling

et al. 2011

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Abstract.CO is a colorless and odorless gas produced by the incomplete combustion of hydrocarbons, both of natural and anthropogenic origin. Several microorganisms, including aerobic and anaerobic bacteria and anaerobic archaea, use exogenous CO as a source of carbon and energy for growth. On the other hand, eukaryotic organisms use endogenous CO, produced during heme degradation, as a neurotransmitter and as a signal molecule. CO sensors act as signal transducers by coupling a ''regulatory'' heme-binding domain to a ''functional'' signal transmitter. Although high CO concentrations inhibit generally heme-protein actions, low CO levels can influence several signaling pathways, including those regulated by soluble guanylate cyclase and/or mitogenactivated protein kinases. This review summarizes recent insights into CO metabolism, sensing, and signaling.

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Section: Co Sensingmentioning

confidence: 99%

“…In the purple nonsulfur bacterium R. rubrum, in the presence of CO, CooA promotes the transcription of genes involved in CO oxidation [61,62]. Both chains of CooA contain a N-terminal sensory domain and a C-terminal DNA-binding domain, connected by the long C-helix [65].…”

Section: Co Sensingmentioning

confidence: 99%

CO metabolism, sensing, and signaling

et al. 2011

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“…(19) and S. coelicolor. 3 For this study, HemY from these organisms was cloned with an aminoterminal His 6 tag, expressed, purified, and characterized. It was found that HemY from these organisms is a soluble monomeric protein with a molecular weight of ϳ47,000 and a bound FAD.…”

Section: Identification Of Hemq As a Required Protein For Hemementioning

confidence: 99%

“…In microorganisms, it is required for energy generation via respiratory chain cytochromes, xenobiotic metabolism by cytochrome P450s, fatty acid desaturation, oxidases, peroxidases, redox (2), and gas sensing (3,4). More recently, a clear role for heme as a regulatory ligand for a variety of transcription factors such as Bach1 and SREBP has been identified (5-7).…”

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confidence: 99%

Discovery and Characterization of HemQ

Dailey

Boynton

Albetel

et al. 2010

Journal of Biological Chemistry

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Here we identify a previously undescribed protein, HemQ, that is required for heme synthesis in Gram-positive bacteria. We have characterized HemQ from Bacillus subtilis and a number of Actinobacteria. HemQ is a multimeric heme-binding protein. Spectroscopic studies indicate that this heme is high spin ferric iron and is ligated by a conserved histidine with the sixth coordination site available for binding a small molecule. The presence of HemQ along with the terminal two pathway enzymes, protoporphyrinogen oxidase (HemY) and ferrochelatase, is required to synthesize heme in vivo and in vitro. Although the exact role played by HemQ remains to be characterized, to be fully functional in vitro it requires the presence of a bound heme. HemQ possesses minimal peroxidase activity, but as a catalase it has a turnover of over 10 4 min ؊1 . We propose that this activity may be required to eliminate hydrogen peroxide that is generated by each turnover of HemY. Given the essential nature of heme synthesis and the restricted distribution of HemQ, this protein is a potential antimicrobial target for pathogens such as Mycobacterium tuberculosis.

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“…Binding of O 2 to the regulatory heme-PAS domain of FixL is involved in the regulation of gene expression in nitrogen-fixing bacteria by inactivating the FixL kinase domain [2]. CO binding to the heme of the transcription factor CooA activates its DNA binding domain, initiating the transcription of enzymes that allow the photosynthetic bacterium Rhodospirillum rubrum to grow on CO as a sole energy source [3]. The generation of the second messenger 3¢-5¢-cyclic guanosine monophosphate by soluble guanylate cyclase (sGC) in mammals is regulated by binding of NO or CO [4].…”

Section: Introductionmentioning

confidence: 99%

Ligand-induced monomerization of Allochromatium vinosum cytochrome c′ studied using native mass spectrometry and fluorescence resonance energy transfer

et al. 2007

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Cytochrome c¢ from Allochromatium vinosum is an attractive model protein to study ligand-induced conformational changes. This homodimeric protein dissociates into monomers upon binding of NO, CO or CN -to the iron of its covalently attached heme group. While ligand binding to the heme has been well characterized using a variety of spectroscopic techniques, direct monitoring of the subsequent monomerization has not been reported previously. Here we have explored two biophysical techniques to simultaneously monitor ligand binding and monomerization. Native mass spectrometry allowed the detection of the dimeric and monomeric forms of cytochrome c¢ and even showed the presence of a CO-bound monomer. The kinetics of the ligand-induced monomerization were found to be significantly enhanced in the gas phase compared with the kinetics in solution, however. Ligand binding to the heme and the dissociation of the dimer in solution were also studied using energy transfer from a fluorescent probe to both heme groups of the protein. Comparison of ligand binding kinetics as observed with UV-vis spectroscopy with changes in fluorescence suggested that binding of one CO molecule per dimer could be sufficient for monomerization.

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CooA, a paradigm for gas sensing regulatory proteins

Cited by 88 publications

References 95 publications

CO metabolism, sensing, and signaling

CO metabolism, sensing, and signaling

Discovery and Characterization of HemQ

Ligand-induced monomerization of Allochromatium vinosum cytochrome c′ studied using native mass spectrometry and fluorescence resonance energy transfer

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