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Application of Genetically Encoded Fluorescent Nitric Oxide (NO•) Probes, the geNOps, for Real-time Imaging of NO• Signals in Single Cells
Published on: March 16, 2017
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A third subunit in ancestral cytochrome c-dependent nitric oxide reductases
C Bricio1, L Alvarez1, M San Martin1
1Centro de Biología Molecular Severo Ochoa, Universidad Autónoma de Madrid-Consejo Superior de Investigaciones Científicas, Madrid, Spain.
Applied and Environmental Microbiology
|June 8, 2014
Summary
Denitrifying bacteria reduce nitric oxide (NO) using quinol-nitric oxide reductase (qNor) or cytochrome c-dependent nitric oxide reductase (cNor). In Thermus thermophilus, a third subunit, NorH, enhances cNor efficiency in denitrification.
Area of Science:
- Microbiology
- Biochemistry
- Environmental Science
Background:
- Denitrification is a crucial microbial process reducing nitrogen oxides.
- Nitric oxide (NO) reduction is catalyzed by quinol-dependent (qNor) or cytochrome c-dependent (cNor) nitric oxide reductases.
- Thermophilic bacteria like Thermus thermophilus possess unique denitrification pathways.
Purpose of the Study:
- To investigate the role of the norH gene in the cytochrome c-dependent nitric oxide reductase (cNor) complex of Thermus thermophilus.
- To elucidate the function of the NorH protein in the denitrification process.
Main Methods:
- Gene expression analysis: confirmed cotranscription of norC, norB, and norH genes.
- Mutagenesis: generated individual nor mutants to assess gene function.
- Protein purification: produced His-tagged NorH protein using immobilized-metal affinity chromatography (IMAC).
Main Results:
- The genes encoding the cNor subunits (norC, norB) and norH are cotranscribed in Thermus thermophilus.
- NorH is a distinct third subunit of the cNor complex in T. thermophilus.
- NorH plays a role in in vivo denitrification, likely by improving electron transport to cNor.
Conclusions:
- NorH is an integral component of the cNor complex in Thermus thermophilus.
- The presence of NorH suggests a more efficient electron transport system for nitric oxide reduction in this bacterium.
- This finding contributes to understanding the diversity and efficiency of denitrification pathways in thermophilic bacteria.
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