Mutational analysis of the dimethylsulfoxide respiratory (dor) operon of Rhodobacter capsulatus

Shaw, Anthony; Leimkuler, Silke; Klipp, Werner; Hanson, Graeme R.; McEwan, Alastair G.

doi:10.1099/13500872-145-6-1409

Cited by 47 publications

(47 citation statements)

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“…Interestingly, disruption of the dorD gene, which encodes a TorD homologue in R. capsulatus, leads to the disappearance of the molybdoenzyme DorA (24). This result points out a relationship between DorD and DorA and suggests that immature DorA is rapidly degraded unless DorD binds to it and allows maturation.…”

Section: Discussionmentioning

confidence: 72%

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Involvement of a Mate Chaperone (TorD) in the Maturation Pathway of Molybdoenzyme TorA

Ilbert¹,

Méjean²,

Giudici‐Orticoni

et al. 2003

Journal of Biological Chemistry

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As many prokaryotic molybdoenzymes, the trimethylamine oxide reductase (TorA) of Escherichia coli requires the insertion of a bis(molybdopterin guanine dinucleotide)molybdenum cofactor in its catalytic site to be active and translocated to the periplasm. We show in vitro that the purified apo form of TorA was activated weakly when an appropriate bis(molybdopterin guanine dinucleotide)molybdenum source was provided, whereas addition of the TorD chaperone increased apoTorA activation up to 4-fold, allowing maturation of most of the apoprotein. We demonstrate that TorD alone is sufficient for the efficient activation of apoTorA by performing a minimal in vitro assay containing only the components for the cofactor synthesis, apoTorA and TorD. Interestingly, incubation of apoTorA with TorD before cofactor addition led to a significant increase of apoTorA activation, suggesting that TorD acts on apoTorA before cofactor insertion. This result is consistent with the fact that TorD binds to apoTorA and probably modifies its conformation in the absence of cofactor. Therefore, we propose that TorD is involved in the first step of TorA maturation to make it competent to receive the cofactor.

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Section: Discussionmentioning

confidence: 72%

“…Moreover, the absence of TorD in E. coli leads to a significant decrease of the amount of TorA (22). Strikingly, in Rhodobacter capsulatus the absence of DorD results in a complete loss of DorA (24). Finally, in an E. coli MGD-deficient strain, an excess of TorD limits the proteolytic degradation of the TorA cytoplasmic apo form (22).…”

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confidence: 98%

Involvement of a Mate Chaperone (TorD) in the Maturation Pathway of Molybdoenzyme TorA

Ilbert¹,

Méjean²,

Giudici‐Orticoni

et al. 2003

Journal of Biological Chemistry

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“…The topology of the trees indicated that dmsB and dmsD are of archaeal evolutionary origin, while for dmsC, no clear correlation with the 16S rRNA phylogenetic tree was observed (data not shown). The small DmsE protein showed some identity (19%) with DorB from Rhodobacter capsulatus, which has been suggested to function in biogenesis of the DMSO reductase in that organism (32).…”

Section: Fig 3 Rt-pcr Analysis Of the Dms Operon Inmentioning

confidence: 99%

“…In Escherichia coli, the molecular components of the DMSO reductase are DmsA, the catalytically active subunit harboring molybdenum-molybdopterin (MPT) as a cofactor; DmsB, a subunit containing iron-sulfur clusters for electron transport; DmsC, a membrane anchor; and DmsD, a molecular chaperone. Other bacterial DMSO and TMAO reductases may contain a membrane-bound c-type cytochrome (DorC or TorC) instead of DmsB and DmsC (17,31,32). The expression of the corresponding dms and tor genes in bacteria may be regulated by a two-component regulatory system (e.g., TorR-TorS) (15,33) or the global oxygen response regulator FNR (6).…”

Section: Comparison Of Dmsrmentioning

confidence: 99%

“…By contrast, in various bacterial model organisms, DMSO reductases and the related TMAO reductases are well characterized as membrane-bound or periplasmic terminal reductases forming dimethyl sulfide or trimethylamine, respectively, as the final product (7,17,19,29,30,32,39). In Escherichia coli, the molecular components of the DMSO reductase are DmsA, the catalytically active subunit harboring molybdenum-molybdopterin (MPT) as a cofactor; DmsB, a subunit containing iron-sulfur clusters for electron transport; DmsC, a membrane anchor; and DmsD, a molecular chaperone.…”

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confidence: 99%

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Genomic Analysis of Anaerobic Respiration in the ArchaeonHalobacteriumsp. Strain NRC-1: Dimethyl Sulfoxide and TrimethylamineN-Oxide as Terminal Electron Acceptors

2005

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We have investigated anaerobic respiration of the archaeal model organism Halobacterium sp. strain NRC-1 by using phenotypic and genetic analysis, bioinformatics, and transcriptome analysis. NRC-1 was found to grow on either dimethyl sulfoxide (DMSO) or trimethylamine N-oxide (TMAO) as the sole terminal electron acceptor, with a doubling time of 1 day. An operon, dmsREABCD, encoding a putative regulatory protein, DmsR, a molybdopterin oxidoreductase of the DMSO reductase family (DmsEABC), and a molecular chaperone (DmsD) was identified by bioinformatics and confirmed as a transcriptional unit by reverse transcriptase PCR analysis. dmsR, dmsA, and dmsD in-frame deletion mutants were individually constructed. Phenotypic analysis demonstrated that dmsR, dmsA, and dmsD are required for anaerobic respiration on DMSO and TMAO. The requirement for dmsR, whose predicted product contains a DNA-binding domain similar to that of the Bat family of activators (COG3413), indicated that it functions as an activator. A cysteine-rich domain was found in the dmsR gene, which may be involved in oxygen sensing. Microarray analysis using a wholegenome 60-mer oligonucleotide array showed that the dms operon is induced during anaerobic respiration. Comparison of dmsR؉ and ⌬dmsR strains by use of microarrays showed that the induction of the dmsEABCD operon is dependent on a functional dmsR gene, consistent with its action as a transcriptional activator. Our results clearly establish the genes required for anaerobic respiration using DMSO and TMAO in an archaeon for the first time.Extremely halophilic archaea (haloarchaea) generally grow heterotrophically under aerobic conditions in hypersaline environments, although they possess facultative anaerobic capabilities (9). These anaerobic capabilities are important since the high salt concentrations and elevated temperatures the organisms encounter, together with high cell densities promoted by aerobic growth and flotation, reduce the availability of molecular oxygen. Although haloarchaeal microorganisms frequently encounter microaerobic or even anoxic conditions, detailed knowledge regarding the extent of haloarchaeal anaerobic growth is still only beginning to emerge. Some species of haloarchaea can carry out primary energy conservation in the absence of molecular oxygen via photophosphorylation (13), substrate-level phosphorylation (13), and anaerobic respiration using nitrate (references 9 and 42 and references therein). In addition, two previous reports described the ability to use dimethyl sulfoxide (DMSO) and trimethylamine-N-oxide (TMAO) (23), and to some extent fumarate (22), as alternative electron acceptors for growth enhancement for some haloarchaea.The molecular basis of the DMSO and TMAO respiratory systems has not been described for any member of the domain Archaea. By contrast, in various bacterial model organisms, DMSO reductases and the related TMAO reductases are well characterized as membrane-bound or periplasmic terminal reductases forming dimethyl sulfide or trimethyla...

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Trimethylamine N ‐Oxide Reductase

Iobbi‐Nivol

Haser²,

M��jean

et al. 2004

Handbook of Metalloproteins

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Trimethylamine N ‐oxide (TMAO) is a compound widely distributed in marine fish and invertebrates; and TMAO reducing enzymes are found not only in marine bacteria and photosynthetic bacteria living in ponds but also in enterobacteria. The various respiratory systems reducing TMAO, described so far, share a high level of homology either in their general structure, or in the regulation or mechanism of electron transfer. According to their content of molybdenum cofactor, the enzymes in charge of TMAO reduction are classified in the structural dimethylsulfoxide (DMSO) reductase family. TMAO reductases, however, in contrast to DMSO reductases are highly specific enzymes and reduce only their physiological substrate. The crystal structure was determined for the TMAO reductase from Shewanella massilia , and its structural differences with DMSO reductases in the environment of the active site. A tyrosine residue in the proximity of the molybdenum ion in DMSO reductases is absent in TMAO reductases and could be related to the differences in substrate specificities.

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Mutational analysis of the dimethylsulfoxide respiratory (dor) operon of Rhodobacter capsulatus

Cited by 47 publications

References 30 publications

Involvement of a Mate Chaperone (TorD) in the Maturation Pathway of Molybdoenzyme TorA

Involvement of a Mate Chaperone (TorD) in the Maturation Pathway of Molybdoenzyme TorA

Genomic Analysis of Anaerobic Respiration in the ArchaeonHalobacteriumsp. Strain NRC-1: Dimethyl Sulfoxide and TrimethylamineN-Oxide as Terminal Electron Acceptors

Trimethylamine N ‐Oxide Reductase

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