Methanopyrus

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Methanopyrus
Scientific classification
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Genus:
Methanopyrus
Binomial name
Methanopyrus
Kurr et al. 1992
Species

In taxonomy, Methanopyrus is a genus of the Methanopyraceae.[1]

Methanopyrus is a genus of methanogen, with a single described species, M. kandleri. It is a hyperthermophile, discovered on the wall of a black smoker from the Gulf of California at a depth of 2000 m, at temperatures of 84–110 °C. Strain 116 was discovered in black smoker fluid of the Kairei hydrothermal field; it can survive and reproduce at 122 °C.[2] It lives in a hydrogen-carbon dioxide rich environment, and like other methanogens reduces the latter to methane. It is placed among the Euryarchaeota, in its own class.

Cell structure[edit]

Methanopyrus kandleri is a rod-shaped methanogen that produces methane from reducing carbon dioxide.[3][4]

Methanopyrus kandleri is different from other archaea because it still has one of the simplest versions of membrane lipids.[3] The membrane of M. kandleri is made of terpenoid lipids, which is a group of lipids containing cholesterol, hopanoids, carotenoid, phytane, and bisphytane.[5] Although terpenoids are the main component of the membrane in M. kandleri, they are more of a supporting structure in eukaryote and bacteria.[5]

Methanopyrus kandleri has a high concentration of cyclic 2,3-diphosphoglycerate.[3] This compound is often found in hyperthermophile, helping to prevent protein denaturation in high temperatures.[6] The increased concentration of cyclic 2,3-diphosphoglycerate protects the methanogen, helping it survive in an environment that many other organisms could not. Beyond this compound to help protect the proteins, M. kandleri also has a high salt concentration inside its membrane.[3] This increased concentration of salt helps with enzyme stability and promotes activity of the enzymes at higher temperatures.[7]

Genomics[edit]

The complete genome of Methanopyrus kandleri was sequenced by researchers at Fidelity Systems. It was determined to be a GC-rich genome containing 1,694,969 nucleotides of which about 62.1% is guanine or cytosine.[3] Overall, the genome of M. kandleri is considered ‘minimalist’ because so few genes have been transferred from other organisms into its own genome. This could be due to the extreme environment that it lives in and the low number of potential transfers it could have because of it.[3]

Research[edit]

Methanopyrus kandleri is also the only species known to have topoisomerase 5. Topoisomerase 5 allows for M. kandleri to survive in such high temperatures and helps to relax both positively and negatively supercoiled DNA .[8] Although topoisomerase 5 is useful in this case, finding other hyperthermophiles that have topoisomerase 5 has proven difficult. Because of this, more research is being done to fully understand how M. kandleri obtained topoisomerase 5, and why no other hyperthermophiles have it.

References[edit]

  1. ^ See the NCBI webpage on Methanopyrus. Data extracted from the "NCBI taxonomy resources". National Center for Biotechnology Information. Retrieved 2007-03-19.
  2. ^ Takai K, Nakamura K, Toki T, Tsunogai U, Miyazaki M, Miyazaki J, et al. (August 2008). "Cell proliferation at 122 degrees C and isotopically heavy CH4 production by a hyperthermophilic methanogen under high-pressure cultivation". Proceedings of the National Academy of Sciences of the United States of America. 105 (31): 10949–54. Bibcode:2008PNAS..10510949T. doi:10.1073/pnas.0712334105. PMC 2490668. PMID 18664583.
  3. ^ a b c d e f Slesarev AI, Mezhevaya KV, Makarova KS, Polushin NN, Shcherbinina OV, Shakhova VV, et al. (April 2002). "The complete genome of hyperthermophile Methanopyrus kandleri AV19 and monophyly of archaeal methanogens". Proceedings of the National Academy of Sciences of the United States of America. 99 (7): 4644–9. doi:10.1073/pnas.032671499. PMID 11930014.
  4. ^ "Euryarchaeota | Boundless Microbiology". courses.lumenlearning.com. Retrieved 2021-04-23.
  5. ^ a b Nakatani Y, Ribeiro N, Streiff S, Gotoh M, Pozzi G, Désaubry L, Milon A (September 2014). "Search for the most 'primitive' membranes and their reinforcers: a review of the polyprenyl phosphates theory". Origins of Life and Evolution of the Biosphere. 44 (3): 197–208. doi:10.1007/s11084-014-9365-6. PMC 4669544. PMID 25351682.
  6. ^ "InterPro". www.ebi.ac.uk. Retrieved 2021-04-23.
  7. ^ Breitung J, Börner G, Scholz S, Linder D, Stetter KO, Thauer RK (December 1992). "Salt dependence, kinetic properties and catalytic mechanism of N-formylmethanofuran:tetrahydromethanopterin formyltransferase from the extreme thermophile Methanopyrus kandleri". European Journal of Biochemistry. 210 (3): 971–81. doi:10.1111/j.1432-1033.1992.tb17502.x. PMID 1483480.
  8. ^ Forterre P (June 2006). "DNA topoisomerase V: a new fold of mysterious origin". Trends in Biotechnology. 24 (6): 245–7. doi:10.1016/j.tibtech.2006.04.006. PMID 16650908.

Further reading[edit]

Scientific databases[edit]

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