Methanococcoides burtonii

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A Microbial Biorealm page on the genus Methanococcoides burtonii

Classification

Higher order taxa

cellular organisms; Archaea; Euryarchaeota; Methanomicrobia; Methanosarcinales; Methanosarcinaceae; Methanococcoides.(5,9)

Species

Methanococcoides burtonii

Description and significance

M. burtonii is an extremophile that love life extremely cold. They live at the bottom of Ace Lake in Antarctica, where there is no oxygen and the average temperature is a brutal 33 degrees Fahrenheit.(7) The in situ temperature is annually 1 to 2°C.(1) It has an optimal growth temperature of 23°C and an upper growth temperature limit of approximately 28°C.(1) One of the most significant findings is that this microbe has flexible proteins, which allow their cells to survive cold temperatures and carry out basic cell functions under extreme conditions. These proteins are more rigid and stable in bacteria that live at higher temperatures.(7)

Genome structure

The determination of the DNA genome sequence of this strain has been or is being determined either in whole or in part.(6)

M. burtonii’s chromosome is circular. Its sequence is RS: NC_007955. The number of nucleotides present is 2575032. It contains 2273 of protein genes and 63 RNA genes.(6)

Cell structure and metabolism

M. burtonii lacks peptidiglycan in its cell wall.

Ecology

Ecological significance is carbon cycle and production of methane.(8)

Pathology

No evidence has been documented to determine whether or not this is a pathogen.

Application to Biotechnology

M. burtonii produces methane which is a colorless, odorless gas which is lighter than air. It is formed by the decomposition of organic carbons under oxygen poor (anaerobic) conditions. M. burtonii is known as a methanogen. Methanogens are unique among organisms in their ability to survive a wide range of temperatures, from the freezing point of water to 185 degrees Fahrenheit and everything in between.(7)

Current Research

The pathway for the synthesis of the organic solute glucosylglycerate (GG) is proposed based on the activities of the recombinant glucosyl-3-phosphoglycerate synthase (GpgS) and glucosyl-3-phosphoglycerate phosphatase (GpgP) from Methanococcoides burtonii. A mannosyl-3-phosphoglycerate phosphatase gene homologue (mpgP) was found in the genome of M. burtonii (http://www.jgi.doe.gov), but an mpgS gene coding for mannosyl-3-phosphoglycerate synthase (MpgS) was absent. The gene upstream of the mpgP homologue encoded a putative glucosyltransferase that was expressed in Escherichia coli. The recombinant product had GpgS activity, catalyzing the synthesis of glucosyl-3-phosphoglycerate (GPG) from GDP-glucose and D-3-phosphoglycerate, with a high substrate specificity. The recombinant MpgP protein dephosphorylated GPG to GG and was also able to dephosphorylate mannosyl-3-phosphoglycerate (MPG) but no other substrate tested.(2)

The role of unsaturated diether lipids (UDLs) in the adaptation of M. burtonii to low temperature was investigated. A proteomics approach and the use of the M. burtonii draft genome sequence identified enzymes involved in lipid biosynthesis and a pathway for lipid biosynthesis, respectively. All the major phospholipid classes contained a series of unsaturated analogues. The proportion of unsaturated lipids from cells grown at 4[degree]C was significantly greater than that from cells grown at 23[degree]C. Reconstruction of the main lipid synthesis pathways suggested that the formation of UDLs may be due to incomplete reduction of an arahaeol precursor rather than to a desaturase mechanism. The results confirm that cold adaptation in M. burtonii involves specific changes in membrane lipid unsaturation.(3)

The effect of temperature on the stability and activity of elongation factor 2 (EF-2) protein from the Antarctic methanogen M. burtonii was investigated. Comparison of the M. burtonii EF-2 with the phylogenetically related thermophile, Methanosarcina thermophila revealed biochemical and biophysical properties characteristic of the cold-adapted protein, including a higher activity at low temperatures due to reduced activation energy necessary for GTP hydrolysis and reduced activation energy for irreversible denaturation of the protein. Additional cytoplasmic factors are likely to be important for the complete thermal adaptation of the proteins in vivo.(4)

The biosynthetic pathway for solute glucosylglycerate in M. burtonii was examined. The genes involved in the synthesis of glucosylglycerate were identified, and the activities of the recombinant enzymes were characterized. The synthesis of glucosylglycerate proceeded via a 2-step pathway involving glucosyl-3-phosphoglycerate synthase and glucosyl-3-phosphoglycerate phosphatase.(2)

References

1. Noon, Kathleen R., Guymon, Rebecca, Crain, Pamela F., McCloskey, James A., Thomm, Michael, Lim, Julianne, Cavicchioli, Ricardo Influence of Temperature on tRNA Modification in Archaea: Methanococcoides burtonii (Optimum Growth Temperature [Topt], 23{degrees}C) and Stetteria hydrogenophila (Topt, 95{degrees}C) J. Bacteriol. 2003 185: 5483-5490

2. Costa, Joana, Empadinhas, Nuno, Goncalves, Luis, Lamosa, Pedro, Santos, Helena, da Costa, Milton S. Characterization of the Biosynthetic Pathway of Glucosylglycerate in the Archaeon Methanococcoides burtonii J. Bacteriol. 2006 188: 1022-1030

3. Nichols, David S., Miller, Matthew R., Davies, Noel W., Goodchild, Amber, Raftery, Mark, Cavicchioli, Ricardo Cold Adaptation in the Antarctic Archaeon Methanococcoides burtonii Involves Membrane Lipid Unsaturation J. Bacteriol. 2004 186: 8508-8515

4. Thomas, Torsten, Cavicchioli, Ricardo Effect of Temperature on Stability and Activity of Elongation Factor 2 Proteins from Antarctic and Thermophilic Methanogens J. Bacteriol. 2000 182: 1328-1332

5. http://archaea.ucsc.edu/cgi-bin/hgGateway?db=methBurt2

6. http://www.ncbi.nlm.nih.gov/Taxonomy/Browser/wwwtax.cgi?id=259564

7. http://www.genomenewsnetwork.org/articles/07_03/extremo.shtml

8. http://www.slideshare.net/neilfws/genomics-of-coldadapted-microorganisms/

9. http://www.ncbi.nlm.nih.gov/Taxonomy/Browser/wwwtax.cgi?

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Edited by student of Rachel Larsen