Methanococcus maripaludis

Methanococcus maripaludis is a species of methanogen found in marine environments, specifically salt marshes.[1] Methanococcus maripaludis is methanogenic and a strict anaerobe. M. maripaludis is apart of the Archaea domain but specifically found in the branch of the Euryarchaeota in this domain. It is apart of the Methanococcaceae family. These bacteria are anaerobic and weakly motile, non-spore-forming, Gram-negative, mesophile, and pleomorphic coccoid-rod shaped, averaging 1.2 by 1.6 μm is size.[2] The genome of M. maripaludis has been sequenced.[3] It has been described as an electric bacteria.[4] It is known to be mesophilic and hydrogentrophic. This specific methanogenic archaea has a role in degrading metals and producing H2 from the metabolic process it takes to degrade these metals. Methanococcus maripaludis grows quickly and doubles within the time frame of two hours. [5]

Methanococcus maripaludis
Scientific classification
Domain:
Archaea
Kingdom:
Euryarchaeota
Phylum:
Euryarchaeota
Class:
Methanococci
Order:
Methanococcales
Family:
Methanococcaceae
Genus:
Methanococcus
Species:
Methanococcus maripaludis

Jones et al. 1984

Metabolism

The metabolic landscape of M. maripaludis consists of eight major subsystems:[1]

Methanogenesis

In M. maripaludis, the primary carbon source for methanogenesis is carbon dioxide, although alternatives such as formate are also viable. The Wolfe cycle is a cyclic pathway by which CO2 and hydrogen gas are converted into methane and H2O.[6] Some strains and mutants of M. maripaludis have been shown to be capable of methanogenesis in the absence of hydrogen gas, though this is uncommon.[7]

Methanogenesis in M. maripaludis occurs in the following steps:

  1. Reduction of CO2 via methanofuran and reduced ferredoxins[8]
  2. Oxidation and subsequent reduction of the coenzyme F420 in the presence of H2[9][8]
  3. Transfer of methyl group from methyl-THMPT to coenzyme M (HS-CoM), driving translocation of 2Na+ across membrane to strengthen the proton gradient[10]
  4. Demethylation of methyl-S-CoM to form methane and generate additional energy via subsequent reduction of byproducts with H2[11]

Cell structure

The cell wall of Methanococcus maripaludis has an S-layer that does not contain peptidoglycan, which helps to identify its domain as Archaea.[3] It has flagella, which confer motility, and pili.[12] These cells use both flagella and pili to attach to surfaces, meaning that if they encounter a desirable environment, they can remain there.[12]

Genetic Characteristics

Methanococcus maripaludis is one of four hydrogenotrophic methanogens, along with Methanocaldococcus jannaschii, Methanothermobacter thermautotrophicus, and Methanopyrus kandleri, to have its genome sequenced.[3] Of these four, Methanocaldococcus jannaschii is the closest living, known relative of M. maripaludis. M. maripaludis, like many other archaea, has one single circular chromosome.[3] Of its 1,722 protein coding genes, 835 ORFs, or open reading frames, have unknown functions, and 129 ORFs are unique to M. maripaludis.[3] According to the number of BlastP hits, or similar protein sequences identified by the Basic Local Alignment Search Tool (BLAST), in in the genome sequence, M. maripaludis is similar to most other methanogens.[3] However, M. maripaludis is missing certain features present in most methanogens, such as the ribulose bisphosphate carboxylase enzyme.[3]

References
  1. Goyal N, Zhou Z, Karimi IA (June 2016). "Metabolic processes of Methanococcus maripaludis and potential applications". Microbial Cell Factories. 15 (1): 107. doi:10.1186/s12934-016-0500-0. PMC 4902934. PMID 27286964.
  2. Jones WJ, Paynter MJ, Gupta R (1983). "Characterization of Methanococcus maripaludis sp. nov., a new methanogen isolated from salt marsh sediment". Archives of Microbiology. 135 (2): 91–97. doi:10.1007/BF00408015. ISSN 0302-8933. S2CID 2025112.
  3. Hendrickson EL, Kaul R, Zhou Y, Bovee D, Chapman P, Chung J, et al. (October 2004). "Complete genome sequence of the genetically tractable hydrogenotrophic methanogen Methanococcus maripaludis". Journal of Bacteriology. 186 (20): 6956–6969. doi:10.1128/JB.186.20.6956-6969.2004. PMC 522202. PMID 15466049.
  4. Deutzmann JS, Sahin M, Spormann AM (April 2015). "Extracellular enzymes facilitate electron uptake in biocorrosion and bioelectrosynthesis". mBio. 6 (2): e00496–15. doi:10.1128/mBio.00496-15. PMC 4453541. PMID 25900658.
  5. Goyal, Nishu; Zhou, Zhi; Karimi, Iftekhar A. (December 2016). "Metabolic processes of Methanococcus maripaludis and potential applications". Microbial Cell Factories. 15 (1): 107. doi:10.1186/s12934-016-0500-0. ISSN 1475-2859. PMC 4902934. PMID 27286964.
  6. Escalante-Semerena, J C; Rinehart, K L; Wolfe, R S (August 10, 1984). "Tetrahydromethanopterin, a carbon carrier in methanogenesis". Journal of Biological Chemistry. 259 (15): 9447–9455. doi:10.1016/s0021-9258(17)42721-9. ISSN 0021-9258. PMID 6547718.
  7. Lohner, Svenja T; Deutzmann, Jörg S; Logan, Bruce E; Leigh, John; Spormann, Alfred M (August 8, 2014). "Hydrogenase-independent uptake and metabolism of electrons by the archaeon Methanococcus maripaludis". The ISME Journal. 8 (8): 1673–1681. doi:10.1038/ismej.2014.82. ISSN 1751-7362. PMC 4817615. PMID 24844759.
  8. Thauer, Rudolf K.; Kaster, Anne-Kristin; Seedorf, Henning; Buckel, Wolfgang; Hedderich, Reiner (2008-06-30). "Methanogenic archaea: ecologically relevant differences in energy conservation". Nature Reviews Microbiology. 6 (8): 579–591. doi:10.1038/nrmicro1931. ISSN 1740-1526. PMID 18587410. S2CID 32698014.
  9. Mukhopadhyay, Biswarup; Stoddard, Steven F.; Wolfe, Ralph S. (1998). "Purification, Regulation, and Molecular and Biochemical Characterization of Pyruvate Carboxylase from Methanobacterium thermoautotrophicum Strain ΔH". Journal of Biological Chemistry. 273 (9): 5155–5166. doi:10.1074/jbc.273.9.5155. ISSN 0021-9258. PMID 9478969.
  10. Kengen, ServéW.M.; Daas, Piet J.H.; Duits, Erik F.G.; Keltjens, Jan T.; van der Drift, Chris; Vogels, Godfried D. (1992). "Isolation of a 5-hydroxybenzimidazolyl cobamide-containing enzyme involved in the methyltetrahydromethanopterin: coenzyme M methyltransferase reaction in Methanobacterium thermoautotrophicum". Biochimica et Biophysica Acta (BBA) - Protein Structure and Molecular Enzymology. 1118 (3): 249–260. doi:10.1016/0167-4838(92)90282-i. ISSN 0167-4838. PMID 1737047.
  11. Kaster, Anne-Kristin; Moll, Johanna; Parey, Kristian; Thauer, Rudolf K. (2011-01-24). "Coupling of ferredoxin and heterodisulfide reduction via electron bifurcation in hydrogenotrophic methanogenic archaea". Proceedings of the National Academy of Sciences. 108 (7): 2981–2986. Bibcode:2011PNAS..108.2981K. doi:10.1073/pnas.1016761108. ISSN 0027-8424. PMC 3041090. PMID 21262829.
  12. Jarrell, Ken (June 1, 2011). "Flagella and pili are both necessary for efficient attachment of Methanococcus maripaludis to surfaces". academic.oup.com. Retrieved 2023-10-05.

Further reading
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