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Updated: Sep 4, 2025
08:08
An Assay for Measuring the Activity of Escherichia coli Inducible Lysine Decarboxyase
Published on: December 19, 2010
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Escherichia coli RclA is a highly active hypothiocyanite reductase
Julia D Meredith1, Irina Chapman2, Kathrin Ulrich3
1Department of Microbiology, Heersink School of Medicine, University of Alabama at Birmingham, Birmingham, AL 35233.
Summary
The flavoprotein RclA protects bacteria like E. coli from the antimicrobial hypothiocyanous acid (HOSCN). This enzyme
Area of Science:
- Microbiology
- Immunology
- Biochemistry
Background:
- Hypothiocyanite/hypothiocyanous acid (OSCN-/HOSCN) is an innate immune antimicrobial.
- HOSCN damages bacteria by oxidizing sulfur-containing amino acids.
- Bacterial resistance mechanisms to HOSCN are not well understood.
Purpose of the Study:
- To identify bacterial genes conferring resistance to HOSCN.
- To investigate the role of RclA in HOSCN detoxification.
- To explore the relevance of HOSCN as a gut antimicrobial.
Main Methods:
- Enzyme assays to measure HOSCN reduction by RclA.
- Genetic manipulation of E. coli and L. reuteri.
- Heterologous expression of RclA homologs in E. coli.
Main Results:
- E. coli flavoprotein RclA efficiently reduces HOSCN to thiocyanate.
- RclA confers strong protection to E. coli against HOSCN toxicity.
- RclA homologs from S. aureus, S. pneumoniae, and B. thetaiotaomicron also provide HOSCN resistance.
Conclusions:
- RclA is a key enzyme for bacterial HOSCN resistance.
- HOSCN may be an important antimicrobial in the gut environment.
- Conserved RclA homologs suggest broad implications in host-microbe interactions.
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