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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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Related in: MedlinePlus

Deletion of DegS and RseA like proteases increases ChrR stability.Stability of ChrR in the R. sphaeroides wild type and strains 2.4.1ΔRSP_3242, 2.4.1ΔRSP_2710 under 1O2 stress conditions (high light 800 W m-2; 50 nM methylene blue). To check ChrR stability under stress conditions, translation was inhibited by adding chloramphenicol (500 µg ml-1) after cultures were exposed for 60 min to 1O2 (time point 0 min). Western blots were developed using α-ChrR and anti-rabbit IgG conjugated with alkaline phosphatase.
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pone-0079520-g009: Deletion of DegS and RseA like proteases increases ChrR stability.Stability of ChrR in the R. sphaeroides wild type and strains 2.4.1ΔRSP_3242, 2.4.1ΔRSP_2710 under 1O2 stress conditions (high light 800 W m-2; 50 nM methylene blue). To check ChrR stability under stress conditions, translation was inhibited by adding chloramphenicol (500 µg ml-1) after cultures were exposed for 60 min to 1O2 (time point 0 min). Western blots were developed using α-ChrR and anti-rabbit IgG conjugated with alkaline phosphatase.

Mentions: The half-life of the lower band clearly increased in the RSP_3242 and RSP_2710 mutants compared to the wild type (Figure 9). In the wild type strain the upper ChrR band had a much longer half-life than the lower band. The half-life of the upper band strongly increased in the RSP_2710 mutant. These data support a contribution of the DegS and RseA homologs in proteolytic degradation of the ChrR anti sigma factor.


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 DegS and RseA like proteases increases ChrR stability.Stability of ChrR in the R. sphaeroides wild type and strains 2.4.1ΔRSP_3242, 2.4.1ΔRSP_2710 under 1O2 stress conditions (high light 800 W m-2; 50 nM methylene blue). To check ChrR stability under stress conditions, translation was inhibited by adding chloramphenicol (500 µg ml-1) after cultures were exposed for 60 min to 1O2 (time point 0 min). Western blots were developed using α-ChrR and anti-rabbit IgG conjugated with alkaline phosphatase.
© Copyright Policy
Related In: Results  -  Collection

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

pone-0079520-g009: Deletion of DegS and RseA like proteases increases ChrR stability.Stability of ChrR in the R. sphaeroides wild type and strains 2.4.1ΔRSP_3242, 2.4.1ΔRSP_2710 under 1O2 stress conditions (high light 800 W m-2; 50 nM methylene blue). To check ChrR stability under stress conditions, translation was inhibited by adding chloramphenicol (500 µg ml-1) after cultures were exposed for 60 min to 1O2 (time point 0 min). Western blots were developed using α-ChrR and anti-rabbit IgG conjugated with alkaline phosphatase.
Mentions: The half-life of the lower band clearly increased in the RSP_3242 and RSP_2710 mutants compared to the wild type (Figure 9). In the wild type strain the upper ChrR band had a much longer half-life than the lower band. The half-life of the upper band strongly increased in the RSP_2710 mutant. These data support a contribution of the DegS and RseA homologs in proteolytic degradation of the ChrR anti sigma factor.

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