Regulation of putative methyl‐sulphide methyltransferases in <i>Methanosarcina acetivorans</i> C2A

Bose, Arpita; Kulkarni, Gargi; Metcalf, William W.

doi:10.1111/j.1365-2958.2009.06864.x

Cited by 21 publications

(30 citation statements)

References 53 publications

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“…The MtpP (MA4166) protein is a member of the major facilitator superfamily (MFS) and is likely to be a transporter for the cognate substrate. Lastly, as noted by Reichlen et al (37), MsrH (MA4167) is a member of the methanol-specific regulator (Msr) family, known to be involved in the transcriptional activation of numerous MT1-/MT2-encoding genes in Methanosarcina (20,38).…”

Section: Resultsmentioning

confidence: 99%

“…These proteins are comprised of an N-terminal corrinoid domain and a C-terminal MT2 domain. Genetic studies showed that these proteins are both required and sufficient for the synthesis and catabolism of DMS, leading to their designation as MtsD, MtsF, and MtsH, respectively (19,20). It was suggested that these proteins catalyze a DMS:CoM methyltransferase reaction analogous to that catalyzed by the MtsA/B system of M. barkeri (19).…”

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confidence: 99%

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Genetic Basis for Metabolism of Methylated Sulfur Compounds in Methanosarcina Species

Metcalf

2015

J Bacteriol

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Methanosarcina acetivorans uses a variety of methylated sulfur compounds as carbon and energy sources. Previous studies implicated the mtsD, mtsF, and mtsH genes in catabolism of dimethylsulfide, but the genes required for use of other methylsulfides have yet to be established. Here, we show that a four-gene locus, designated mtpCAP-msrH, is specifically required for growth on methylmercaptopropionate (MMPA). The mtpC, mtpA, and mtpP genes encode a putative corrinoid protein, a coenzyme M (CoM) methyltransferase, and a major facilitator superfamily (MFS) transporter, respectively, while msrH encodes a putative transcriptional regulator. Mutants lacking mtpC or mtpA display a severe growth defect in MMPA medium but are unimpaired during growth on other substrates. The mtpCAP genes comprise a transcriptional unit that is highly and specifically upregulated during growth on MMPA, whereas msrH is monocistronic and constitutively expressed. Mutants lacking msrH fail to transcribe mtpCAP and grow poorly in MMPA medium, consistent with the assignment of its product as a transcriptional activator. The mtpCAP-msrH locus is conserved in numerous marine methanogens, including eight Methanosarcina species that we showed are capable of growth on MMPA. Mutants lacking the mtsD, mtsF, and mtsH genes display a 30% reduction in growth yield when grown on MMPA, suggesting that these genes play an auxiliary role in MMPA catabolism. A quadruple ⌬mtpCAP ⌬mtsD ⌬mtsF ⌬mtsH mutant strain was incapable of growth on MMPA. Reanalysis of mtsD, mtsF, and mtsH mutants suggests that the preferred substrate for MtsD is dimethylsulfide, while the preferred substrate for MtsF is methanethiol. IMPORTANCEMethylated sulfur compounds play pivotal roles in the global sulfur and carbon cycles and contribute to global temperature homeostasis. Although the degradation of these molecules by aerobic bacteria has been well studied, relatively little is known regarding their fate in anaerobic ecosystems. In this study, we identify the genetic basis for metabolism of methylmercaptopropionate, dimethylsulfide, and methanethiol by strictly anaerobic methanogens of the genus Methanosarcina. These data will aid the development of predictive sulfur cycle models and enable molecular ecological approaches for the study of methylated sulfur metabolism in anaerobic ecosystems. M ethylated sulfur compounds (generically known as methylsulfides), including methylmercaptopropionate (MMPA), dimethylsulfide (DMS), and methanethiol (MeSH), are abundant in many ecosystems and play pivotal roles in the global sulfur and carbon cycles (1, 2). The predominate source of methylsulfides in marine systems is believed to be dimethylsulfoniopropionate (DMSP), a compatible solute whose synthesis by marine algae is estimated to account for 1 to 10% of global primary production (3). DMSP is degraded via two distinct microbial metabolic processes: the cleavage pathway and the demethylation pathway (1). The majority of DMSP (50 to 90%) is degraded via the demethylation pathway, pr...

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Section: Resultsmentioning

confidence: 99%

mentioning

confidence: 99%

Genetic Basis for Metabolism of Methylated Sulfur Compounds in Methanosarcina Species

Metcalf

2015

J Bacteriol

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“…Although these groups have no experimentally studied representatives, their exclusive affiliation with methyldegrading methanogens suggests that these Mts homologs relate to methanogenic methyl metabolism. Family I is unlikely to support MeSH, DMS or MMPA metabolism as Methanosarcina acetivorans C2A does not express MA0847 during growth on these substrates (Bose et al, 2009;Fu and Metcalf, 2015). Thus, the metabolic function of family I-related WSA2 Mts-like protein (MtlA) is unclear.…”

Section: Uniquely Restricted Methanogenic Metabolismmentioning

confidence: 99%

Chasing the elusive Euryarchaeota class WSA2: genomes reveal a uniquely fastidious methyl-reducing methanogen

et al. 2016

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The ecophysiology of one candidate methanogen class WSA2 (or Arc I) remains largely uncharacterized, despite the long history of research on Euryarchaeota methanogenesis. To expand our understanding of methanogen diversity and evolution, we metagenomically recover eight draft genomes for four WSA2 populations. Taxonomic analyses indicate that WSA2 is a distinct class from other Euryarchaeota. None of genomes harbor pathways for CO 2 -reducing and aceticlastic methanogenesis, but all possess H 2 and CO oxidation and energy conservation through H 2 -oxidizing electron confurcation and internal H 2 cycling. As the only discernible methanogenic outlet, they consistently encode a methylated thiol coenzyme M methyltransferase. Although incomplete, all draft genomes point to the proposition that WSA2 is the first discovered methanogen restricted to methanogenesis through methylated thiol reduction. In addition, the genomes lack pathways for carbon fixation, nitrogen fixation and biosynthesis of many amino acids. Acetate, malonate and propionate may serve as carbon sources. Using methylated thiol reduction, WSA2 may not only bridge the carbon and sulfur cycles in eutrophic methanogenic environments, but also potentially compete with CO 2 -reducing methanogens and even sulfate reducers. These findings reveal a remarkably unique methanogen 'Candidatus Methanofastidiosum methylthiophilus' as the first insight into the sixth class of methanogens 'Candidatus Methanofastidiosa'.

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“…The msrC gene is located adjacent to mtsF, and MtsF protein expression was abolished in the msrC deletion mutant, suggesting a regulatory role for MsrC in DMS metabolism (37). The fact that we observe reduced abundance of MsrC in ΔpylT along with increased MtsX expression indicates that the regulatory system associated with DMS metabolism is complex and may involve multiple regulatory components.…”

Section: Metabolic Adaptations In Methanogensis Withoutmentioning

confidence: 55%

“…We hypothesize that, in the pylT mutant, MsrC is one component of a regulatory system that senses reduced metabolic efficiency from methanol methanogenesis and stimulates production of MtsF and MtsD. Expression profiling of the MtsX genes indicated that their abundance is low in methanol-grown cells, but their mRNA abundance increases between 2-and 50-fold when DMS is added to the media (37). The MtsX enzymes are essential for DMS catabolism when DMS is the sole carbon source, but the same enzymes are involved in DMS formation in cells grown on carbon monoxide (35,39).…”

Section: Metabolic Adaptations In Methanogensis Withoutmentioning

confidence: 99%

Reducing the genetic code induces massive rearrangement of the proteome

O’Donoghue

Prat²,

Kucklick

et al. 2014

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

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Expanding the genetic code is an important aim of synthetic biology, but some organisms developed naturally expanded genetic codes long ago over the course of evolution. Less than 1% of all sequenced genomes encode an operon that reassigns the stop codon UAG to pyrrolysine (Pyl), a genetic code variant that results from the biosynthesis of Pyl-tRNA Pyl . To understand the selective advantage of genetically encoding more than 20 amino acids, we constructed a markerless tRNA Pyl deletion strain of Methanosarcina acetivorans (ΔpylT) that cannot decode UAG as Pyl or grow on trimethylamine. Phenotypic defects in the ΔpylT strain were evident in minimal medium containing methanol. Proteomic analyses of wild type (WT) M. acetivorans and ΔpylT cells identified 841 proteins from >7,000 significant peptides detected by MS/MS. Protein production from UAG-containing mRNAs was verified for 19 proteins. Translation of UAG codons was verified by MS/MS for eight proteins, including identification of a Pyl residue in PylB, which catalyzes the first step of Pyl biosynthesis. Deletion of tRNA Pyl globally altered the proteome, leading to >300 differentially abundant proteins. Reduction of the genetic code from 21 to 20 amino acids led to significant down-regulation in translation initiation factors, amino acid metabolism, and methanogenesis from methanol, which was offset by a compensatory (100-fold) up-regulation in dimethyl sulfide metabolic enzymes. The data show how a natural proteome adapts to genetic code reduction and indicate that the selective value of an expanded genetic code is related to carbon source range and metabolic efficiency.evolution | genetic code expansion | methanogenesis | pyrrolysine | tRNA Pyl

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Regulation of putative methyl‐sulphide methyltransferases in Methanosarcina acetivorans C2A

Cited by 21 publications

References 53 publications

Genetic Basis for Metabolism of Methylated Sulfur Compounds in Methanosarcina Species

Genetic Basis for Metabolism of Methylated Sulfur Compounds in Methanosarcina Species

Chasing the elusive Euryarchaeota class WSA2: genomes reveal a uniquely fastidious methyl-reducing methanogen

Reducing the genetic code induces massive rearrangement of the proteome

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