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DegS and RseP homologous proteases are involved in singlet oxygen dependent activation of RpoE in Rhodobacter sphaeroides.

Nuss AM, Adnan F, Weber L, Berghoff BA, Glaeser J, Klug G - PLoS ONE (2013)

Bottom Line: Moreover, we revealed that the DegS and RseP homologs RSP_3242 and RSP_2710 contribute to (1)O2 resistance and promote ChrR proteolysis.The RpoE signaling pathway in R. sphaeroides is therefore highly similar to that of Escherichia coli, although very different anti-sigma factors control RpoE activity.Based on the acquired results, the current model for RpoE activation in response to (1)O2 exposure in R. sphaeroides was extended.

View Article: PubMed Central - PubMed

Affiliation: Institute of Microbiology and Molecular Biology, Giessen University, Giessen, Germany ; Department of Molecular Infection Biology, Helmholtz Centre for Infection Research, Braunschweig, Germany.

ABSTRACT
Singlet oxygen ((1)O2) is the main agent of photooxidative stress and is generated by photosensitizers as (bacterio)chlorophylls. It leads to the damage of cellular macromolecules and therefore photosynthetic organisms have to mount an adaptive response to (1)O2 formation. A major player of the photooxidative stress response in Rhodobacter sphaeroides is the alternative sigma factor RpoE, which is inactivated under non-stress conditions by its cognate anti-sigma factor ChrR. By using random mutagenesis we identified RSP_1090 to be required for full activation of the RpoE response under (1)O2 stress, but not under organic peroxide stress. In this study we show that both RSP_1090 and RSP_1091 are required for full resistance towards (1)O2. Moreover, we revealed that the DegS and RseP homologs RSP_3242 and RSP_2710 contribute to (1)O2 resistance and promote ChrR proteolysis. The RpoE signaling pathway in R. sphaeroides is therefore highly similar to that of Escherichia coli, although very different anti-sigma factors control RpoE activity. Based on the acquired results, the current model for RpoE activation in response to (1)O2 exposure in R. sphaeroides was extended.

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Deletion of the degS and rseP homologous genes RSP_3242 and RSP_2710 affects sensitivity to 1O2.Inhibition of growth of the R. sphaeroides wild type 2.4.1, strains 2.4.1ΔRSP_1096/1097, 2.4.1ΔRSP_3242, 2.4.1ΔRSP_2710 and TF18(rpoEchrR-) by 1O2. The data represent the mean of three independent experiments. Error bars indicate the standard deviation.
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pone-0079520-g007: Deletion of the degS and rseP homologous genes RSP_3242 and RSP_2710 affects sensitivity to 1O2.Inhibition of growth of the R. sphaeroides wild type 2.4.1, strains 2.4.1ΔRSP_1096/1097, 2.4.1ΔRSP_3242, 2.4.1ΔRSP_2710 and TF18(rpoEchrR-) by 1O2. The data represent the mean of three independent experiments. Error bars indicate the standard deviation.

Mentions: Less efficient proteolytic degradation of ChrR should result in lower activity of RpoE and consequently in lower resistance to 1O2. Therefore we tested the sensitivity of all three mutants against this substance. Strain 2.4.1ΔRSP_1096-1097 showed similar sensitivity in inhibition zone assays as the parental wild type strain, indicating no major role of the deleted genes in RpoE signaling (Figure 7). In contrast, the strains 2.4.1ΔRSP_3242 and 2.4.1ΔRSP_2710 showed significantly increased sensitivity against 1O2 when compared to the wild type. Their sensitivity was, however, lower than that of strain TF18.


DegS and RseP homologous proteases are involved in singlet oxygen dependent activation of RpoE in Rhodobacter sphaeroides.

Nuss AM, Adnan F, Weber L, Berghoff BA, Glaeser J, Klug G - PLoS ONE (2013)

Deletion of the degS and rseP homologous genes RSP_3242 and RSP_2710 affects sensitivity to 1O2.Inhibition of growth of the R. sphaeroides wild type 2.4.1, strains 2.4.1ΔRSP_1096/1097, 2.4.1ΔRSP_3242, 2.4.1ΔRSP_2710 and TF18(rpoEchrR-) by 1O2. The data represent the mean of three independent experiments. Error bars indicate the standard deviation.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3818230&req=5

pone-0079520-g007: Deletion of the degS and rseP homologous genes RSP_3242 and RSP_2710 affects sensitivity to 1O2.Inhibition of growth of the R. sphaeroides wild type 2.4.1, strains 2.4.1ΔRSP_1096/1097, 2.4.1ΔRSP_3242, 2.4.1ΔRSP_2710 and TF18(rpoEchrR-) by 1O2. The data represent the mean of three independent experiments. Error bars indicate the standard deviation.
Mentions: Less efficient proteolytic degradation of ChrR should result in lower activity of RpoE and consequently in lower resistance to 1O2. Therefore we tested the sensitivity of all three mutants against this substance. Strain 2.4.1ΔRSP_1096-1097 showed similar sensitivity in inhibition zone assays as the parental wild type strain, indicating no major role of the deleted genes in RpoE signaling (Figure 7). In contrast, the strains 2.4.1ΔRSP_3242 and 2.4.1ΔRSP_2710 showed significantly increased sensitivity against 1O2 when compared to the wild type. Their sensitivity was, however, lower than that of strain TF18.

Bottom Line: Moreover, we revealed that the DegS and RseP homologs RSP_3242 and RSP_2710 contribute to (1)O2 resistance and promote ChrR proteolysis.The RpoE signaling pathway in R. sphaeroides is therefore highly similar to that of Escherichia coli, although very different anti-sigma factors control RpoE activity.Based on the acquired results, the current model for RpoE activation in response to (1)O2 exposure in R. sphaeroides was extended.

View Article: PubMed Central - PubMed

Affiliation: Institute of Microbiology and Molecular Biology, Giessen University, Giessen, Germany ; Department of Molecular Infection Biology, Helmholtz Centre for Infection Research, Braunschweig, Germany.

ABSTRACT
Singlet oxygen ((1)O2) is the main agent of photooxidative stress and is generated by photosensitizers as (bacterio)chlorophylls. It leads to the damage of cellular macromolecules and therefore photosynthetic organisms have to mount an adaptive response to (1)O2 formation. A major player of the photooxidative stress response in Rhodobacter sphaeroides is the alternative sigma factor RpoE, which is inactivated under non-stress conditions by its cognate anti-sigma factor ChrR. By using random mutagenesis we identified RSP_1090 to be required for full activation of the RpoE response under (1)O2 stress, but not under organic peroxide stress. In this study we show that both RSP_1090 and RSP_1091 are required for full resistance towards (1)O2. Moreover, we revealed that the DegS and RseP homologs RSP_3242 and RSP_2710 contribute to (1)O2 resistance and promote ChrR proteolysis. The RpoE signaling pathway in R. sphaeroides is therefore highly similar to that of Escherichia coli, although very different anti-sigma factors control RpoE activity. Based on the acquired results, the current model for RpoE activation in response to (1)O2 exposure in R. sphaeroides was extended.

Show MeSH
Related in: MedlinePlus