Sequencing, chromosomal inactivation, and functional expression in Escherichia coli of ppsR, a gene which represses carotenoid and bacteriochlorophyll synthesis in Rhodobacter sphaeroides

Penfold, Robert J.; Pemberton, John

doi:10.1128/jb.176.10.2869-2876.1994

Cited by 113 publications

(118 citation statements)

References 54 publications

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“…Sequence analysis indicates that R. capsulatus CrtJ contains three Cys residues located at amino acids 22, 249, and 420. Cys-249 and -420 were identified as attractive targets for mutational analysis because they are also conserved in a CrtJ homolog from Rhodobacter sphaeroides (19). Furthermore, Cys-420 is also very near the C-terminal helix-turn-helix DNA-binding motif located at amino acid residues 426-463 (19).…”

Section: Mutational Analysis Of Cys Residues In Crtjmentioning

confidence: 99%

“…Cys-249 and -420 were identified as attractive targets for mutational analysis because they are also conserved in a CrtJ homolog from Rhodobacter sphaeroides (19). Furthermore, Cys-420 is also very near the C-terminal helix-turn-helix DNA-binding motif located at amino acid residues 426-463 (19). For our in vivo studies, we constructed individual Cys to Ala mutants at all three locations and recombined the mutations into the chromosomal copy of crtJ.…”

Section: Mutational Analysis Of Cys Residues In Crtjmentioning

confidence: 99%

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Repression of photosynthesis gene expression by formation of a disulfide bond in CrtJ

Masuda

Dong

Swem

et al. 2002

Proc. Natl. Acad. Sci. U.S.A.

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Many species of purple photosynthetic bacteria repress synthesis of their photosystem in the presence of molecular oxygen. The bacterium Rhodobacter capsulatus mediates this process by repressing expression of bacteriochlorophyll, carotenoid, and lightharvesting genes via the aerobic repressor, CrtJ. In this study, we demonstrate that CrtJ forms an intramolecular disulfide bond in vitro and in vivo when exposed to oxygen. Mutational and sulfhydryl-specific chemical modification studies indicate that formation of a disulfide bond is critical for CrtJ binding to its target promoters. Analysis of the redox states of aerobically and anaerobically grown cells indicates that they have similar redox states of approximately ؊200 mV, thereby demonstrating that a change in midpoint potential is not responsible for disulfide bond formation. In vivo and in vitro analyses indicate that disulfide bond formation in CrtJ is insensitive to the addition of hydrogen peroxide but is sensitive to molecular oxygen. These results suggest that disulfide bond formation in CrtJ may differ from the mechanism of disulfide bond formation used by OxyR.

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Section: Mutational Analysis Of Cys Residues In Crtjmentioning

confidence: 99%

Section: Mutational Analysis Of Cys Residues In Crtjmentioning

confidence: 99%

Repression of photosynthesis gene expression by formation of a disulfide bond in CrtJ

Masuda

Dong

Swem

et al. 2002

Proc. Natl. Acad. Sci. U.S.A.

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“…The locus upstream of ppsR had previously been identified by Penfold & Pemberton (1994) in R. sphaeroides strain RS630 and designated ppsS (GenBank accession no. L19596).…”

Section: The Ppaa Protein Familymentioning

confidence: 99%

“…highly pigmented and genetically unstable in the presence of oxygen (data not shown). Penfold & Pemberton (1994) suggested that the ppsR gene promoter is located between the NcoI sites used for VKm r cassette insertion. It is likely that an VKm r cassette in strain PPA1 has a polar effect on the downstream ppsR gene, thus making PPA1 in effect a double ppaA ppsR mutant.…”

Section: Construction Of the Ppaa Mutantsmentioning

confidence: 99%

Identification and in vivo characterization of PpaA, a regulator of photosystem formation in Rhodobacter sphaeroides

et al. 2003

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“…Reduced AppA can reduce and bind the repressor protein PpsR, which contains two conserved cystein residues and undergoes a redoxdependent disulfide-dithiol switch (8). Under aerobic conditions, oxidized PpsR binds to the promoter regions of certain photosynthesis genes and represses their transcription (13)(14)(15). At low oxygen tension, reduced AppA and PpsR form a complex, and repression is released (8).…”

mentioning

confidence: 99%

A eukaryotic BLUF domain mediates light-dependent gene expression in the purple bacterium Rhodobacter sphaeroides 2.4.1

Han

Braatsch

Osterloh

et al. 2004

Proc. Natl. Acad. Sci. U.S.A.

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The flavin-binding BLUF domain functions as a blue-light receptor in eukaryotes and bacteria. In the photoreceptor protein photoactivated adenylyl cyclase (PAC) from the flagellate Euglena gracilis, the BLUF domain is linked to an adenylyl cyclase domain. The PAC protein mediates a photophobic response. In the AppA protein of Rhodobacter sphaeroides, the BLUF domain is linked to a downstream domain without similarity to known proteins. AppA functions as a transcriptional antirepressor, controlling photosynthesis gene expression in the purple bacterium R. sphaeroides in response to light and oxygen. We fused the PAC␣1-BLUF domain from Euglena to the C terminus of AppA. Our results show that the hybrid protein is fully functional in light-dependent gene repression in R. sphaeroides, despite only Ϸ30% identity between the eukaryotic and the bacterial BLUF domains. Furthermore, the bacterial BLUF domain and the C terminus of AppA can transmit the light signal even when expressed as separated domains. This finding implies that the BLUF domain is fully modular and can relay signals to completely different output domains.

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Sequencing, chromosomal inactivation, and functional expression in Escherichia coli of ppsR, a gene which represses carotenoid and bacteriochlorophyll synthesis in Rhodobacter sphaeroides

Cited by 113 publications

References 54 publications

Repression of photosynthesis gene expression by formation of a disulfide bond in CrtJ

Repression of photosynthesis gene expression by formation of a disulfide bond in CrtJ

Identification and in vivo characterization of PpaA, a regulator of photosystem formation in Rhodobacter sphaeroides

A eukaryotic BLUF domain mediates light-dependent gene expression in the purple bacterium Rhodobacter sphaeroides 2.4.1

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