Characterization of redox-active cysteine residues of persulfide-responsive transcriptional repressor SqrR
We recently identified the novel persulfide sensor SqrR that functions as a master regulator of sulfide-dependent gene expression in the purple photosynthetic bacterium Rhodobacter capsulatus. SqrR binds to the promoter regions of target genes to repress their expression in the absence of sulfide, a...
| Main Authors: | , |
|---|---|
| Format: | Article |
| Language: | English |
| Published: |
Taylor & Francis Group
2017-07-01
|
| Series: | Communicative & Integrative Biology |
| Subjects: | |
| Online Access: | http://dx.doi.org/10.1080/19420889.2017.1329786 |
| _version_ | 1818931688804188160 |
|---|---|
| author | Takayuki Shimizu Shinji Masuda |
| author_facet | Takayuki Shimizu Shinji Masuda |
| author_sort | Takayuki Shimizu |
| collection | DOAJ |
| description | We recently identified the novel persulfide sensor SqrR that functions as a master regulator of sulfide-dependent gene expression in the purple photosynthetic bacterium Rhodobacter capsulatus. SqrR binds to the promoter regions of target genes to repress their expression in the absence of sulfide, and the repressor activity is negated by sulfide treatment. SqrR has 3 cysteine residues, 2 of which are conserved in SqrR homologs from other bacteria: Cys41 and Cys107. SqrR forms an intramolecular tetrasulfide bond between Cys41 and Cys107 when exposed to persulfide, which results in loss of the DNA-binding activity in vitro. Here, we address the mechanism through which these cysteine residues are modified by persulfides. We show that the predicted pKa value of Cys107, as revealed by a putative SqrR structural model, is lower than that of Cys41. Furthermore, C41S SqrR in which Cys41 was changed to serine forms an intermolecular disulfide-bond between Cys107 of 2 SqrRs, suggesting high nucleophilic reactivity of Cy107. These data suggest that Cys107 and Cys41 function as attacking Cys and resolving Cys, respectively; this occurs during tetrasulfide-bond formation of WT SqrR, when it is exposed to persulfide. |
| first_indexed | 2024-12-20T04:20:34Z |
| format | Article |
| id | doaj.art-800f1e8ba7984e6d95c3b0c8987ebcca |
| institution | Directory Open Access Journal |
| issn | 1942-0889 |
| language | English |
| last_indexed | 2024-12-20T04:20:34Z |
| publishDate | 2017-07-01 |
| publisher | Taylor & Francis Group |
| record_format | Article |
| series | Communicative & Integrative Biology |
| spelling | doaj.art-800f1e8ba7984e6d95c3b0c8987ebcca2022-12-21T19:53:38ZengTaylor & Francis GroupCommunicative & Integrative Biology1942-08892017-07-0110410.1080/19420889.2017.13297861329786Characterization of redox-active cysteine residues of persulfide-responsive transcriptional repressor SqrRTakayuki Shimizu0Shinji Masuda1Tokyo Institute of TechnologyTokyo Institute of TechnologyWe recently identified the novel persulfide sensor SqrR that functions as a master regulator of sulfide-dependent gene expression in the purple photosynthetic bacterium Rhodobacter capsulatus. SqrR binds to the promoter regions of target genes to repress their expression in the absence of sulfide, and the repressor activity is negated by sulfide treatment. SqrR has 3 cysteine residues, 2 of which are conserved in SqrR homologs from other bacteria: Cys41 and Cys107. SqrR forms an intramolecular tetrasulfide bond between Cys41 and Cys107 when exposed to persulfide, which results in loss of the DNA-binding activity in vitro. Here, we address the mechanism through which these cysteine residues are modified by persulfides. We show that the predicted pKa value of Cys107, as revealed by a putative SqrR structural model, is lower than that of Cys41. Furthermore, C41S SqrR in which Cys41 was changed to serine forms an intermolecular disulfide-bond between Cys107 of 2 SqrRs, suggesting high nucleophilic reactivity of Cy107. These data suggest that Cys107 and Cys41 function as attacking Cys and resolving Cys, respectively; this occurs during tetrasulfide-bond formation of WT SqrR, when it is exposed to persulfide.http://dx.doi.org/10.1080/19420889.2017.1329786cysteine (Cys)hydrogen sulfidepersulfidepurple bacteriareactive sulfur speciesRhodobacterSqrRsulfide sensor |
| spellingShingle | Takayuki Shimizu Shinji Masuda Characterization of redox-active cysteine residues of persulfide-responsive transcriptional repressor SqrR Communicative & Integrative Biology cysteine (Cys) hydrogen sulfide persulfide purple bacteria reactive sulfur species Rhodobacter SqrR sulfide sensor |
| title | Characterization of redox-active cysteine residues of persulfide-responsive transcriptional repressor SqrR |
| title_full | Characterization of redox-active cysteine residues of persulfide-responsive transcriptional repressor SqrR |
| title_fullStr | Characterization of redox-active cysteine residues of persulfide-responsive transcriptional repressor SqrR |
| title_full_unstemmed | Characterization of redox-active cysteine residues of persulfide-responsive transcriptional repressor SqrR |
| title_short | Characterization of redox-active cysteine residues of persulfide-responsive transcriptional repressor SqrR |
| title_sort | characterization of redox active cysteine residues of persulfide responsive transcriptional repressor sqrr |
| topic | cysteine (Cys) hydrogen sulfide persulfide purple bacteria reactive sulfur species Rhodobacter SqrR sulfide sensor |
| url | http://dx.doi.org/10.1080/19420889.2017.1329786 |
| work_keys_str_mv | AT takayukishimizu characterizationofredoxactivecysteineresiduesofpersulfideresponsivetranscriptionalrepressorsqrr AT shinjimasuda characterizationofredoxactivecysteineresiduesofpersulfideresponsivetranscriptionalrepressorsqrr |