The redox-sensing mechanism of Agrobacterium tumefaciens NieR as a thiol-based oxidation sensor for hypochlorite stress
Issued Date
2023-11-01
Resource Type
ISSN
08915849
eISSN
18734596
Scopus ID
2-s2.0-85167621779
Pubmed ID
37544488
Journal Title
Free Radical Biology and Medicine
Volume
208
Start Page
211
End Page
220
Rights Holder(s)
SCOPUS
Bibliographic Citation
Free Radical Biology and Medicine Vol.208 (2023) , 211-220
Suggested Citation
Nontaleerak B., Eurtivong C., Weeraphan C., Buncherd H., Chokchaichamnankit D., Srisomsap C., Svasti J., Sukchawalit R., Mongkolsuk S. The redox-sensing mechanism of Agrobacterium tumefaciens NieR as a thiol-based oxidation sensor for hypochlorite stress. Free Radical Biology and Medicine Vol.208 (2023) , 211-220. 220. doi:10.1016/j.freeradbiomed.2023.08.002 Retrieved from: https://repository.li.mahidol.ac.th/handle/20.500.14594/88365
Title
The redox-sensing mechanism of Agrobacterium tumefaciens NieR as a thiol-based oxidation sensor for hypochlorite stress
Other Contributor(s)
Abstract
NieR is a TetR family transcriptional repressor previously shown to regulate the NaOCl-inducible efflux pump NieAB in Agrobacterium tumefaciens. NieR is an ortholog of Escherichia coli NemR that specifically senses hypochlorite through the redox switch of a reversible sulfenamide bond between C106 and K175. The amino acid sequence of NieR contains only one cysteine. NieR has C104 and R166, which correspond to C106 and K175 of NemR, respectively. The aim of this study was to investigate the redox-sensing mechanism of NieR under NaOCl stress. C104 and R166 were subjected to mutagenesis to determine their roles. Although the substitution of R166 by alanine slightly reduced its DNA-binding activity, NieR retained its repressor function. By contrast, the DNA-binding and repression activities of NieR were completely lost when C104 was replaced by alanine. C104 substitution with serine only partially impaired the repressor function. Mass spectrometry analysis revealed an intermolecular disulfide bond between the C104 residues of NieR monomers. This study demonstrates the engagement of C104 in the mechanism of NaOCl sensing. C104 oxidation induced the formation of a disulfide-linked dimer that was likely to alter conformation, thus abolishing the DNA-binding ability of NieR and derepressing the target genes.