Respiratory pathways of Rhodobacter sphaeroides 2.4.1T: identification and characterization of genes encoding quinol oxidases

Mouncey, N

doi:10.1016/s0378-1097(00)00433-x

Cited by 3 publications

(4 citation statements)

References 13 publications

(21 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The slow aerobic growth of strain CYT-2/Y suggests impairment in the aerobic respiratory chain, most likely a restriction in flow of electrons from the bc 1 complex to the cytochrome c oxidases. The change in pigmentation of these cells is consistent with previous observations in R. sphaeroides 2.4.1 demonstrating that disruption of electron flow, because of the loss of these two cytochromes, results in the aerobic expression of light-harvesting complexes (Mouncey et al, 2000;Oh & Kaplan, 1999). …”

Section: Disruption Of Cyca and Cycysupporting

confidence: 91%

Electron transfer to nitrite reductase of Rhodobacter sphaeroides 2.4.3: examination of cytochromes c 2 and c Y

2006

View full text Add to dashboard Cite

The role of cytochrome c 2 , encoded by cycA, and cytochrome c Y , encoded by cycY, in electron transfer to the nitrite reductase of Rhodobacter sphaeroides 2.4.3 was investigated using both in vivo and in vitro approaches. Both cycA and cycY were isolated, sequenced and insertionally inactivated in strain 2.4.3. Deletion of either gene alone had no apparent effect on the ability of R. sphaeroides to reduce nitrite. In a cycA-cycY double mutant, nitrite reduction was largely inhibited. However, the expression of the nitrite reductase gene nirK from a heterologous promoter substantially restored nitrite reductase activity in the double mutant. Using purified protein, a turnover number of 5 s . The turnover experiments indicate that c 2 is a major electron donor to nitrite reductase but c Y is probably not. Taken together, these results suggest that there is likely an unidentified electron donor, in addition to c 2 , that transfers electrons to nitrite reductase, and that the decreased nitrite reductase activity observed in the cycA-cycY double mutant probably results from a change in nirK expression.

show abstract

Section: Disruption Of Cyca and Cycysupporting

confidence: 91%

Electron transfer to nitrite reductase of Rhodobacter sphaeroides 2.4.3: examination of cytochromes c 2 and c Y

2006

View full text Add to dashboard Cite

show abstract

“…The expression level of the Qxt quinol oxidase (RSP3210-RSP3212) was low and downregulated at 15 min. The second quinol oxidase, Qox (RSP3097-RSP3098) (55), and another putative cytochrome oxidase (RSP0117-RSP0118), which were found by genome analyses, were not expressed under the tested conditions (data not shown). These two oxidases, as has been previously reported, have never been shown to be expressed.…”

Section: Discussionmentioning

confidence: 95%

Transcriptome Dynamics during the Transition from Anaerobic Photosynthesis to Aerobic Respiration in Rhodobacter sphaeroides 2.4.1

2008

View full text Add to dashboard Cite

Rhodobacter sphaeroides 2.4.1 is a facultative photosynthetic anaerobe that grows by anoxygenic photosynthesis under anaerobic-light conditions. Changes in energy generation pathways under photosynthetic and aerobic respiratory conditions are primarily controlled by oxygen tensions. In this study, we performed time series microarray analyses to investigate transcriptome dynamics during the transition from anaerobic photosynthesis to aerobic respiration. Major changes in gene expression profiles occurred in the initial 15 min after the shift from anaerobic-light to aerobic-dark conditions, with changes continuing to occur up to 4 hours postshift. Those genes whose expression levels changed significantly during the time series were grouped into three major classes by clustering analysis. Class I contained genes, such as that for the aa 3 cytochrome oxidase, whose expression levels increased after the shift. Class II contained genes, such as those for the photosynthetic apparatus and Calvin cycle enzymes, whose expression levels decreased after the shift. Class III contained genes whose expression levels temporarily increased during the time series. Many genes for metabolism and transport of carbohydrates or lipids were significantly induced early during the transition, suggesting that those endogenous compounds were initially utilized as carbon sources. Oxidation of those compounds might also be required for maintenance of redox homeostasis after exposure to oxygen. Genes for the repair of protein and sulfur groups and uptake of ferric iron were temporarily upregulated soon after the shift, suggesting they were involved in a response to oxidative stress. The flagellar-biosynthesis genes were expressed in a hierarchical manner at 15 to 60 min after the shift. Numerous transporters were induced at various time points, suggesting that the cellular composition went through significant changes during the transition from anaerobic photosynthesis to aerobic respiration. Analyses of these data make it clear that numerous regulatory activities come into play during the transition from one homeostatic state to another.

show abstract

“…This appears to be correct since (i) the upstream sequences of operons coding for two quinone oxidases in R. sphaeroides have no discernable FNR consensus-like sequence [71], (ii) FnrL participates in a multilayered regulatory mechanism that, in the presence of DMSO and in the absence of oxygen, leads to activation of DMSO reductase genes [61]; (iii) FnrL has no role in the expression of genes associated with the denitrification metabolism which exists among some strains of R. sphaeroides [72,73] and (iv) it is clear that with respect to photosynthesis genes, additional regulatory factors are involved (see below).…”

Section: System I: Regulation Mediated By Molecular Oxygenmentioning

confidence: 99%

“…'Substrate' denotes electron source. Further information on the various enzyme complexes can be found in the following references: Photosynthesis light-harvesting and reaction center pigment-protein complexes [12 -16]; dimethyl sulfoxide reductase complex [60,61]; aa 3 -type cytochrome c oxidase [62,63]; cbb 3 -type cytochrome c oxidase [58,59,125]; quinol oxidases [71]. relating to energy capture and then describe the differences and similarities between photosynthesis that involves the generation of oxygen and photosynthesis that does not lead to oxygen generation.…”

Section: Introductionmentioning

confidence: 99%

Oxygen intervention in the regulation of gene expression: the photosynthetic bacterial paradigm

Zeilstra-Ryalls

Kaplan²

2004

Cellular and Molecular Life Sciences (CMLS)

View full text Add to dashboard Cite

The means by which oxygen intervenes in gene expression has been examined in considerable detail in the metabolically versatile bacterium Rhodobacter sphaeroides. Three regulatory systems are now known in this organism, which are used singly and in combination to modulate genes in response to changing oxygen availability. The outcome of these regulatory events is that the molecular machinery is present for the cell to obtain energy by means that are best suited to prevailing conditions, while at the same time maintaining cellular redox balance. Here, we explore the dangers associated with molecular oxygen relative to the various metabolisms used by R. sphaeroides, and then present the most recent findings regarding the features and operation of each of the three regulatory systems which collectively mediate oxygen control in this organism.

show abstract

Respiratory pathways of Rhodobacter sphaeroides 2.4.1T: identification and characterization of genes encoding quinol oxidases

Cited by 3 publications

References 13 publications

Electron transfer to nitrite reductase of Rhodobacter sphaeroides 2.4.3: examination of cytochromes c 2 and c Y

Electron transfer to nitrite reductase of Rhodobacter sphaeroides 2.4.3: examination of cytochromes c 2 and c Y

Transcriptome Dynamics during the Transition from Anaerobic Photosynthesis to Aerobic Respiration in Rhodobacter sphaeroides 2.4.1

Oxygen intervention in the regulation of gene expression: the photosynthetic bacterial paradigm

Contact Info

Product

Resources

About