scholarly journals Evidence for the role of redox carriers in photosynthesis gene expression and carotenoid biosynthesis in Rhodobacter sphaeroides 2.4.1.

1997 ◽  
Vol 179 (6) ◽  
pp. 1951-1961 ◽  
Author(s):  
J P O'Gara ◽  
S Kaplan
Keyword(s):  
Gene Expression ◽  
Rhodobacter Sphaeroides ◽  
Carotenoid Biosynthesis ◽  
Photosynthesis Gene

scholarly journals Genetic and Phenotypic Analyses of therdx Locus of Rhodobacter sphaeroides2.4.1

2000 ◽  
Vol 182 (12) ◽  
pp. 3475-3481 ◽  
Author(s):  
Jung Hyeob Roh ◽  
Samuel Kaplan
Keyword(s):  
Gene Expression ◽  
Rhodobacter Sphaeroides ◽  
Redox Protein ◽  
Deletion Mutations ◽  
Metal Transporter ◽  
New Class ◽  
Mutant Strains ◽  
Membrane Bound ◽  
Photosynthesis Gene

ABSTRACT Previously, we reported that rdxB, encoding a likely membrane-bound two [4Fe-4S]-containing center, is involved in the aerobic regulation of photosystem gene expression in Rhodobacter sphaeroides 2.4.1. To further investigate the role ofrdxB as well as other genes of the rdxBHISoperon on photosystem gene expression, we constructed a series of nonpolar, in-frame deletion mutations in each of the rdxgenes. Using both puc and puf operonlacZ fusions to monitor photosystem gene expression, under aerobic conditions, in each of the mutant strains revealed significant increased photosynthesis gene expression. In the case of mutations in either rdxH, rdxI, or rdxS, the aerobic induction of photosystem gene expression is believed to be indirect by virtue of a posttranscriptional effect oncbb 3 cytochrome oxidase structure and integrity. For RdxB, we suggest that this redox protein has a more direct effect on photosystem gene expression by virtue of its interaction with the cbb 3 oxidase. An associated phenotype, involving the enhanced conversion of the carotenoid spheroidene to spheroidenone, is also observed in the RdxB, -H, -I, and -S mutant strains. This phenotype is also suggested to be the result of the role of the rdxBHIS locus incbb 3 oxidase activity and/or structure. RdxI is suggested to be a new class of metal transporter of the CPx-type ATPases.

scholarly journals Dominant Role of the cbb3 Oxidase in Regulation of Photosynthesis Gene Expression through the PrrBA System in Rhodobacter sphaeroides 2.4.1

2007 ◽  
Vol 189 (15) ◽  
pp. 5617-5625 ◽  
Author(s):  
Yong-Jin Kim ◽  
In-Jeong Ko ◽  
Jin-Mok Lee ◽  
Ho-Young Kang ◽  
Young Min Kim ◽  
...  
Keyword(s):  
Gene Expression ◽  
Rhodobacter Sphaeroides ◽  
Transmembrane Domain ◽  
Dominant Role ◽  
Mutant Form ◽  
Two Component System ◽  
Signaling Function ◽  
Membrane Bound ◽  
Binding Sequence ◽  
Photosynthesis Gene

ABSTRACT In this study, the H303A mutant form of the cbb 3 oxidase (H303A oxidase), which has the H303A mutation in its catalytic subunit (CcoN), was purified from Rhodobacter sphaeroides. The H303A oxidase showed the same catalytic activity as did the wild-type form of the oxidase (WT oxidase). The heme contents of the mutant and WT forms of the cbb 3 oxidase were also comparable. However, the puf and puc operons, which are under the control of the PrrBA two-component system, were shown to be derepressed aerobically in the R. sphaeroides strain expressing the H303A oxidase. Since the strain harboring the H303A oxidase exhibited the same cytochrome c oxidase activity as the stain harboring the WT oxidase did, the aerobic derepression of photosynthesis gene expression observed in the H303A mutant appears to be the result of a defective signaling function of the H303A oxidase rather than reflecting any redox changes in the ubiquinone/ubiquinol pool. It was also demonstrated that ubiquinone inhibits not only the autokinase activity of full-length PrrB but also that of the truncated form of PrrB lacking its transmembrane domain, including the proposed quinone binding sequence. These results imply that the suggested ubiquinone binding site within the PrrB transmembrane domain is not necessary for the inhibition of PrrB kinase activity by ubiquinone. Instead, it is probable that signaling through H303 of the CcoN subunit of the cbb 3 oxidase is part of the pathway through which the cbb 3 oxidase affects the relative kinase/phosphatase activity of the membrane-bound PrrB.

scholarly journals The PpaA/AerR Regulators of Photosynthesis Gene Expression from Anoxygenic Phototrophic Proteobacteria Contain Heme-Binding SCHIC Domains

2010 ◽  
Vol 192 (19) ◽  
pp. 5253-5256 ◽  
Author(s):  
Oleg V. Moskvin ◽  
Marie-Alda Gilles-Gonzalez ◽  
Mark Gomelsky
Keyword(s):  
Gene Expression ◽  
Rhodobacter Sphaeroides ◽  
Binding Domain ◽  
Heme Binding ◽  
Domain Family ◽  
Sequence Identity ◽  
Photosynthesis Gene

ABSTRACT The SCHIC domain of the B12-binding domain family present in the Rhodobacter sphaeroides AppA protein binds heme and senses oxygen. Here we show that the predicted SCHIC domain PpaA/AerR regulators also bind heme and respond to oxygen in vitro, despite their low sequence identity with AppA.

scholarly journals Hierarchical Regulation of Photosynthesis Gene Expression by the Oxygen-Responsive PrrBA and AppA-PpsR Systems of Rhodobacter sphaeroides

2008 ◽  
Vol 190 (24) ◽  
pp. 8106-8114 ◽  
Author(s):  
Larissa Gomelsky ◽  
Oleg V. Moskvin ◽  
Rachel A. Stenzel ◽  
Denise F. Jones ◽  
Timothy J. Donohue ◽  
...  
Keyword(s):  
Gene Expression ◽  
Rhodobacter Sphaeroides ◽  
Response Regulator ◽  
Photosynthetic Apparatus ◽  
Regulatory System ◽  
Structural Proteins ◽  
Gene Encoding ◽  
Genes Encoding ◽  
Photosynthetic Complexes ◽  
Photosynthesis Gene

ABSTRACT In the facultatively phototrophic proteobacterium Rhodobacter sphaeroides, formation of the photosynthetic apparatus is oxygen dependent. When oxygen tension decreases, the response regulator PrrA of the global two-component PrrBA system is believed to directly activate transcription of the puf, puh, and puc operons, encoding structural proteins of the photosynthetic complexes, and to indirectly upregulate the photopigment biosynthesis genes bch and crt. Decreased oxygen also results in inactivation of the photosynthesis-specific repressor PpsR, bringing about derepression of the puc, bch, and crt operons. We uncovered a hierarchical relationship between these two regulatory systems, earlier thought to function independently. We also more accurately assessed the spectrum of gene targets of the PrrBA system. First, expression of the appA gene, encoding the PpsR antirepressor, is PrrA dependent, which establishes one level of hierarchical dominance of the PrrBA system over AppA-PpsR. Second, restoration of the appA transcript to the wild-type level is insufficient for rescuing phototrophic growth impairment of the prrA mutant, whereas inactivation of ppsR is sufficient. This suggests that in addition to controlling appA transcription, PrrA affects the activity of the AppA-PpsR system via an as yet unidentified mechanism(s). Third, PrrA directly activates several bch and crt genes, traditionally considered to be the PpsR targets. Therefore, in R. sphaeroides, the global PrrBA system regulates photosynthesis gene expression (i) by rigorous control over the photosynthesis-specific AppA-PpsR regulatory system and (ii) by extensive direct transcription activation of genes encoding structural proteins of photosynthetic complexes as well as genes encoding photopigment biosynthesis enzymes.

scholarly journals Interdependent Expression of the ccoNOQP-rdxBHIS Loci in Rhodobacter sphaeroides 2.4.1

2002 ◽  
Vol 184 (19) ◽  
pp. 5330-5338 ◽  
Author(s):  
Jung Hyeob Roh ◽  
Samuel Kaplan
Keyword(s):  
Gene Expression ◽  
Gene Cluster ◽  
Rhodobacter Sphaeroides ◽  
Northern Blot Analysis ◽  
Signal Transduction Pathway ◽  
Reverse Transcription Pcr ◽  
Microaerobic Conditions ◽  
Fusion Analysis ◽  
Transcriptional Start Sites ◽  
Photosynthesis Gene

ABSTRACT The rdxBHIS gene cluster of Rhodobacter sphaeroides 2.4.1, located downstream of the ccoNOQP operon encoding the cbb 3 cytochrome c oxidase, is required for the posttranscriptional modification of the cbb 3 cytochrome c oxidase. The cbb 3 cytochrome c oxidase is the main terminal oxidase under microaerobic conditions, as well as a component of the signal transduction pathway controlling photosynthesis gene expression. Because of the intimate functional and positional relationships of the ccoNOQP operon and the rdxBHIS gene cluster, we have examined the transcriptional activities of this DNA region in order to understand their expression and regulation. Northern blot analysis and reverse transcription-PCR, together with earlier complementation analysis, suggested that the ccoNOQP-rdxBHIS cluster is transcribed as ccoNOQP-, ccoNOQP-rdxBH-, rdxBH-, and rdxIS-specific transcripts. Multiple transcriptional start sites have been identified by primer extension analyses: five for ccoN, four for rdxB, and one for rdxI. Transcription from P1N of ccoN and P1B of rdxB is dependent on the presence of FnrL. LacZ fusion analysis support the above-described studies, especially the importance of FnrL. Expression of the cco-rdx cluster is closely related to photosynthesis gene expression, suggesting that transcript stoichiometry and presumably the stoichiometry of the gene products are critical factors in controlling photosynthesis gene expression.

scholarly journals Interacting Regulatory Circuits Involved in Orderly Control of Photosynthesis Gene Expression in Rhodobacter sphaeroides 2.4.1

2000 ◽  
Vol 182 (11) ◽  
pp. 3081-3087 ◽  
Author(s):  
Jeong-Il Oh ◽  
Jesus M. Eraso ◽  
Samuel Kaplan
Keyword(s):  
Gene Expression ◽  
Complex Formation ◽  
Mutant Strain ◽  
Rhodobacter Sphaeroides ◽  
Photosynthetic Apparatus ◽  
Aerobic Conditions ◽  
Multiple Loci ◽  
Regulatory Circuits ◽  
Spectral Complex

ABSTRACT FnrL, the homolog of the global anaerobic regulator Fnr, is required for the induction of the photosynthetic apparatus inRhodobacter sphaeroides 2.4.1. Thus, the precise role of FnrL in photosynthesis (PS) gene expression and its interaction(s) with other regulators of PS gene expression are of considerable importance to our understanding of the regulatory circuitry governing spectral complex formation. Using a CcoP and FnrL double mutant strain, we obtained results which suggested that FnrL is not involved in the transduction of the inhibitory signal, by which PS gene expression is “silenced,” emanating from thecbb 3 oxidase encoded by the ccoNOQPoperon under aerobic conditions. The dominant effect of theccoP mutation in the FnrL mutant strain with respect to spectral complex formation under aerobic conditions and restoration of a PS-positive phenotype suggested that inactivation of thecbb 3 oxidase to some extent bypasses the requirement for FnrL in the formation of spectral complexes. Additional analyses revealed that anaerobic induction of thebchE, hemN, and hemZ genes, which are involved in the tetrapyrrole biosynthetic pathways, requires FnrL. Thus, FnrL appears to be involved at multiple loci involved in the regulation of PS gene expression. Additionally, bchE was also shown to be regulated by the PrrBA two-component system, in conjunction with hemN and hemZ. These and other results to be discussed permit us to more accurately describe the role of FnrL as well as the interactions between the FnrL, PrrBA, and other regulatory circuits in the regulation of PS gene expression.

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