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Pathway Description
Nitric oxide - HcpR
Porphyromonas gingivalis
Category:
Metabolite Pathway
Sub-Category:
Signaling
Created: 2025-03-25
Last Updated: 2025-07-31
The nitric oxide (NO) effector pathway is a bacterial defense system that protects cells from the toxic effects of nitric oxide, a reactive nitrogen species produced by host immune responses or environmental sources. This pathway is regulated by HcpR, a transcriptional regulator that activates genes involved in nitrosative stress resistance.
HcpR belongs to the Crp/Fnr family of transcription factors and is activated in response to elevated nitric oxide levels. Upon sensing NO, HcpR promotes the expression of genes that help detoxify NO and repair NO-induced cellular damage.
Key genes in the HcpR regulog include:
ytfE – Encodes a di-iron protein involved in iron-sulfur (Fe-S) cluster repair. Fe-S clusters are particularly sensitive to nitric oxide, and YtfE helps restore their function, which is critical for maintaining cellular respiration and redox balance under NO stress.
hcp – Encodes the hybrid cluster protein, which can act as a nitric oxide reductase or electron carrier involved in NO detoxification. Hcp plays a central role in protecting the cell by reducing NO to less toxic nitrogen compounds.
References
Nitric oxide - HcpR References
Cossart P, Gicquel-Sanzey B: Cloning and sequence of the crp gene of Escherichia coli K 12. Nucleic Acids Res. 1982 Feb 25;10(4):1363-78. doi: 10.1093/nar/10.4.1363.
Pubmed: 6280141
Aiba H, Fujimoto S, Ozaki N: Molecular cloning and nucleotide sequencing of the gene for E. coli cAMP receptor protein. Nucleic Acids Res. 1982 Feb 25;10(4):1345-61. doi: 10.1093/nar/10.4.1345.
Pubmed: 6280140
Blattner FR, Plunkett G 3rd, Bloch CA, Perna NT, Burland V, Riley M, Collado-Vides J, Glasner JD, Rode CK, Mayhew GF, Gregor J, Davis NW, Kirkpatrick HA, Goeden MA, Rose DJ, Mau B, Shao Y: The complete genome sequence of Escherichia coli K-12. Science. 1997 Sep 5;277(5331):1453-62. doi: 10.1126/science.277.5331.1453.
Pubmed: 9278503
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