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Cinnamaldehyde Targets the LytTR DNA-Binding Domain of the Response Regulator AgrA to Attenuate Biofilm Formation of Listeria monocytogenes
The Agr quorum sensing (QS) system is known to contribute to biofilm formation in Listeria monocytogenes. Cinnamaldehyde, a natural food preservative, is considered an inhibitor of Agr-mediated QS in L. monocytogenes. However, the exact mechanism by which cinnamaldehyde acts on Agr remains unclear....
Autores principales: | , , , , , , , |
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Formato: | Online Artículo Texto |
Lenguaje: | English |
Publicado: |
American Society for Microbiology
2023
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Materias: | |
Acceso en línea: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10269664/ https://www.ncbi.nlm.nih.gov/pubmed/37140461 http://dx.doi.org/10.1128/spectrum.00300-23 |
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author | Jiang, Xiaobing Kang, Rui Yu, Tao Jiang, Xiaojie Chen, Hong Zhang, Yiping Li, Yi Wang, Hailei |
author_facet | Jiang, Xiaobing Kang, Rui Yu, Tao Jiang, Xiaojie Chen, Hong Zhang, Yiping Li, Yi Wang, Hailei |
author_sort | Jiang, Xiaobing |
collection | PubMed |
description | The Agr quorum sensing (QS) system is known to contribute to biofilm formation in Listeria monocytogenes. Cinnamaldehyde, a natural food preservative, is considered an inhibitor of Agr-mediated QS in L. monocytogenes. However, the exact mechanism by which cinnamaldehyde acts on Agr remains unclear. In this study, we assessed the effects of cinnamaldehyde on the histidine kinase AgrC and the response regulator AgrA in the Agr system. AgrC kinase activity was not influenced by cinnamaldehyde, and binding between AgrC and cinnamaldehyde was not observed when microscale thermophoresis (MST) was performed, indicating that AgrC was not the target of cinnamaldehyde. AgrA is specifically bound to the agr promoter (P(2)) to activate the transcription of the Agr system. However, AgrA-P(2) binding was prevented by cinnamaldehyde. The interaction between cinnamaldehyde and AgrA was further confirmed with MST. Two conserved amino acids, Asn-178 and Arg-179, located in the LytTR DNA-binding domain of AgrA, were identified as the key sites for cinnamaldehyde-AgrA binding by alanine mutagenesis and MST. Coincidentally, Asn-178 was also involved in the AgrA-P(2) interaction. Taken together, these results suggest that cinnamaldehyde acts as a competitive inhibitor of AgrA in AgrA-P(2) binding, which leads to suppressed transcription of the Agr system and reduced biofilm formation in L. monocytogenes. IMPORTANCE Listeria monocytogenes can form biofilms on various food contact surfaces, posing a serious threat to food safety. Biofilm formation of L. monocytogenes is positively regulated by the Agr quorum sensing system. Thus, an alternative strategy for controlling L. monocytogenes biofilms is interfering with the Agr system. Cinnamaldehyde is considered an inhibitor of the L. monocytogenes Agr system; however, its exact mechanism of action is still unclear. Here, we found that AgrA (response regulator), rather than AgrC (histidine kinase), was the target of cinnamaldehyde. The conserved Asn-178 in the LytTR DNA-binding domain of AgrA was involved in cinnamaldehyde-AgrA and AgrA-P(2) binding. Therefore, the occupation of Asn-178 by cinnamaldehyde suppressed transcription of the Agr system and reduced biofilm formation in L. monocytogenes. Our findings could provide a better understanding of the mechanism by which cinnamaldehyde inhibits L. monocytogenes biofilm formation. |
format | Online Article Text |
id | pubmed-10269664 |
institution | National Center for Biotechnology Information |
language | English |
publishDate | 2023 |
publisher | American Society for Microbiology |
record_format | MEDLINE/PubMed |
spelling | pubmed-102696642023-06-16 Cinnamaldehyde Targets the LytTR DNA-Binding Domain of the Response Regulator AgrA to Attenuate Biofilm Formation of Listeria monocytogenes Jiang, Xiaobing Kang, Rui Yu, Tao Jiang, Xiaojie Chen, Hong Zhang, Yiping Li, Yi Wang, Hailei Microbiol Spectr Research Article The Agr quorum sensing (QS) system is known to contribute to biofilm formation in Listeria monocytogenes. Cinnamaldehyde, a natural food preservative, is considered an inhibitor of Agr-mediated QS in L. monocytogenes. However, the exact mechanism by which cinnamaldehyde acts on Agr remains unclear. In this study, we assessed the effects of cinnamaldehyde on the histidine kinase AgrC and the response regulator AgrA in the Agr system. AgrC kinase activity was not influenced by cinnamaldehyde, and binding between AgrC and cinnamaldehyde was not observed when microscale thermophoresis (MST) was performed, indicating that AgrC was not the target of cinnamaldehyde. AgrA is specifically bound to the agr promoter (P(2)) to activate the transcription of the Agr system. However, AgrA-P(2) binding was prevented by cinnamaldehyde. The interaction between cinnamaldehyde and AgrA was further confirmed with MST. Two conserved amino acids, Asn-178 and Arg-179, located in the LytTR DNA-binding domain of AgrA, were identified as the key sites for cinnamaldehyde-AgrA binding by alanine mutagenesis and MST. Coincidentally, Asn-178 was also involved in the AgrA-P(2) interaction. Taken together, these results suggest that cinnamaldehyde acts as a competitive inhibitor of AgrA in AgrA-P(2) binding, which leads to suppressed transcription of the Agr system and reduced biofilm formation in L. monocytogenes. IMPORTANCE Listeria monocytogenes can form biofilms on various food contact surfaces, posing a serious threat to food safety. Biofilm formation of L. monocytogenes is positively regulated by the Agr quorum sensing system. Thus, an alternative strategy for controlling L. monocytogenes biofilms is interfering with the Agr system. Cinnamaldehyde is considered an inhibitor of the L. monocytogenes Agr system; however, its exact mechanism of action is still unclear. Here, we found that AgrA (response regulator), rather than AgrC (histidine kinase), was the target of cinnamaldehyde. The conserved Asn-178 in the LytTR DNA-binding domain of AgrA was involved in cinnamaldehyde-AgrA and AgrA-P(2) binding. Therefore, the occupation of Asn-178 by cinnamaldehyde suppressed transcription of the Agr system and reduced biofilm formation in L. monocytogenes. Our findings could provide a better understanding of the mechanism by which cinnamaldehyde inhibits L. monocytogenes biofilm formation. American Society for Microbiology 2023-05-04 /pmc/articles/PMC10269664/ /pubmed/37140461 http://dx.doi.org/10.1128/spectrum.00300-23 Text en Copyright © 2023 Jiang et al. https://creativecommons.org/licenses/by/4.0/This is an open-access article distributed under the terms of the Creative Commons Attribution 4.0 International license (https://creativecommons.org/licenses/by/4.0/) . |
spellingShingle | Research Article Jiang, Xiaobing Kang, Rui Yu, Tao Jiang, Xiaojie Chen, Hong Zhang, Yiping Li, Yi Wang, Hailei Cinnamaldehyde Targets the LytTR DNA-Binding Domain of the Response Regulator AgrA to Attenuate Biofilm Formation of Listeria monocytogenes |
title | Cinnamaldehyde Targets the LytTR DNA-Binding Domain of the Response Regulator AgrA to Attenuate Biofilm Formation of Listeria monocytogenes |
title_full | Cinnamaldehyde Targets the LytTR DNA-Binding Domain of the Response Regulator AgrA to Attenuate Biofilm Formation of Listeria monocytogenes |
title_fullStr | Cinnamaldehyde Targets the LytTR DNA-Binding Domain of the Response Regulator AgrA to Attenuate Biofilm Formation of Listeria monocytogenes |
title_full_unstemmed | Cinnamaldehyde Targets the LytTR DNA-Binding Domain of the Response Regulator AgrA to Attenuate Biofilm Formation of Listeria monocytogenes |
title_short | Cinnamaldehyde Targets the LytTR DNA-Binding Domain of the Response Regulator AgrA to Attenuate Biofilm Formation of Listeria monocytogenes |
title_sort | cinnamaldehyde targets the lyttr dna-binding domain of the response regulator agra to attenuate biofilm formation of listeria monocytogenes |
topic | Research Article |
url | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10269664/ https://www.ncbi.nlm.nih.gov/pubmed/37140461 http://dx.doi.org/10.1128/spectrum.00300-23 |
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