Citric Acid Controls the Activity of YopH Bacterial Tyrosine Phosphatase

Abstract

Purpose

Citric acid (CA) is a tricarboxylic acid with antioxidant and antimicrobial properties. Based on previous studies, the small compound with its three carboxylic groups can be considered a protein tyrosine phosphatase inhibitor. YopH, a protein tyrosine phosphatase, is an essential virulence factor in Yersinia bacteria.

Materials and Methods

We performed enzymatic activity assays of YopH phosphatase after treatment with citric acid in comparison with the inhibitory compound trimesic acid, which has a similar structure. We also measured the cytotoxicity of these compounds in Jurkat T E6.1 and macrophage J774.2 cell lines. We performed molecular docking analysis of the binding of citric acid molecules to YopH phosphatase.

Results

Citric acid and trimesic acid reversibly reduced the activity of YopH enzyme and decreased the viability of Jurkat and macrophage cell lines. Importantly, these two compounds showed greater inhibitory properties against bacterial YopH activity than against human CD45 phosphatase activity. Molecular docking simulations confirmed that citric acid could bind to YopH phosphatase.

Conclusion

Citric acid, a known antioxidant, can be considered an inhibitor of bacterial phosphatases.

Keywords:

• protein tyrosine phosphatase
• citric acid
• trimesic acid
• bacterial virulence factors
• YopH
• Yersinia
• CD45 phosphatase

Acknowledgments

M.G.-P. acknowledges ST46 (Medical University of Gdansk, Poland).

Disclosure

The authors declare no conflict of interest. The funders had no role in the design of the study; in the collection, analyses, or interpretation of data; in the writing of the manuscript; or in the decision to publish the results.

Additional information

Funding

This research was funded by IDUB Program’s Research Project for Young Scientists MTN No. 71-1215 (Medical University of Gdansk, Poland).