''Methanocaldococcus jannaschii'' (formerly ''Methanococcus jannaschii'') is a

thermophilic A thermophile is an organism—a type of extremophile—that thrives at relatively high temperatures, between . Many thermophiles are archaea, though they can be bacteria or fungi. Thermophilic eubacteria are suggested to have been among the earl ...

methanogenic

archaea Archaea ( ; singular archaeon ) is a domain of single-celled organisms. These microorganisms lack cell nuclei and are therefore prokaryotes. Archaea were initially classified as bacteria, receiving the name archaebacteria (in the Archaebac ...

n in the class

Methanococci Methanococci is a class of methanogenic archaea in the phylum Euryarchaeota.See the NCBIbr>webpage on Methanococci Data extracted from the They can be mesophilic, thermophilic or hyperthermophilic A hyperthermophile is an organism that thri ...

. It was the first archaeon to have its complete genome

sequenced In genetics and biochemistry, sequencing means to determine the primary structure (sometimes incorrectly called the primary sequence) of an unbranched biopolymer. Sequencing results in a symbolic linear depiction known as a sequence which suc ...

. The sequencing identified many genes unique to the archaea. Many of the synthesis pathways for methanogenic

cofactors Cofactor may also refer to: * Cofactor (biochemistry), a substance that needs to be present in addition to an enzyme for a certain reaction to be catalysed * A domain parameter in elliptic curve cryptography, defined as the ratio between the order ...

were worked out biochemically in this organism, as were several other archaeal-specific metabolic pathways.

History

''Methanocaldococcus jannaschii'' was isolated from a submarine hydrothermal vent at

Woods Hole Oceanographic Institution The Woods Hole Oceanographic Institution (WHOI, acronym pronounced ) is a private, nonprofit research and higher education facility dedicated to the study of marine science and engineering. Established in 1930 in Woods Hole, Massachusetts, it ...

Sequencing

''Methanocaldococcus jannaschii'' was sequenced by a group at

TIGR TIGR, an abbreviation for ''Trst'', ''Istra'', ''Gorica'', and ''Reka'', full name Revolutionary Organization of the Julian March T.I.G.R. ( sl, Revolucionarna organizacija Julijske krajine T.I.G.R.), was a militant anti-fascist and insurgent or ...

led by

Craig Venter John Craig Venter (born October 14, 1946) is an American biotechnologist and businessman. He is known for leading one of the first draft sequences of the human genome and assembled the first team to transfect a cell with a synthetic chromosome. ...

using whole-genome

shotgun sequencing In genetics, shotgun sequencing is a method used for sequencing random DNA strands. It is named by analogy with the rapidly expanding, quasi-random shot grouping of a shotgun. The chain-termination method of DNA sequencing ("Sanger sequencing ...

. ''Methanocaldococcus jannaschii'' represented the first member of the Archaea to have its genome sequenced. According to Venter, the unique features of the genome provided strong evidence that there are three domains of life.

Taxonomy

''Methanocaldoccus jannaschii'' is a member of the genus ''

Methanocaldococcus ''Methanocaldococcus'' formerly known as ''Methanococcus'' is a genus of coccoid methanogen archaea. They are all mesophiles, except the thermophilic ''M. thermolithotrophicus'' and the hyperthermophilic ''M. jannaschii''. The latter was discov ...

'' (previously a part of '' Methanococcus'') and is therefore sometimes referred to as a "class I" methanogen (e.g

.

Biology and biochemistry

''Methanocaldococcus jannaschii'' is a thermophilic methanogen, meaning it grows by methanogenesis, making methane as a metabolic byproduct. It is only capable of growth on

carbon dioxide Carbon dioxide ( chemical formula ) is a chemical compound made up of molecules that each have one carbon atom covalently double bonded to two oxygen atoms. It is found in the gas state at room temperature. In the air, carbon dioxide is trans ...

and

hydrogen Hydrogen is the chemical element with the symbol H and atomic number 1. Hydrogen is the lightest element. At standard conditions hydrogen is a gas of diatomic molecules having the formula . It is colorless, odorless, tasteless, non-toxic ...

as primary energy sources, unlike many other methanococci (such as '' Methanococcus maripaludis'') which can also use formate as a primary energy source. The genome includes many

hydrogenase A hydrogenase is an enzyme that catalyses the reversible oxidation of molecular hydrogen (H2), as shown below: Hydrogen uptake () is coupled to the reduction of electron acceptors such as oxygen, nitrate, sulfate, carbon dioxide (), and fumarat ...

s, such as a

5,10-methenyltetrahydromethanopterin hydrogenase The 5,10-methenyltetrahydromethanopterin hydrogenase (or Hmd), the so-called iron-sulfur cluster-free hydrogenase, is an enzyme found in methanogenic archea such as ''Methanothermobacter marburgensis''. It was discovered and first characterized b ...

, a

ferredoxin hydrogenase In enzymology, ferredoxin hydrogenase (), also referred to as e-Fehydrogenase, H2 oxidizing hydrogenase, H2 producing hydrogenase, bidirectional hydrogenase, hydrogenase (ferredoxin), hydrogenlyase, and uptake hydrogenase, is found in ''Clost ...

(eha), and a

coenzyme F420 hydrogenase In enzymology, a coenzyme F420 hydrogenase () is an enzyme that catalyzes the chemical reaction :H2 + coenzyme F420 \rightleftharpoons reduced coenzyme F420 Thus, the two substrates of this enzyme are H2 and coenzyme F420, whereas its product ...

Proteomic Proteomics is the large-scale study of proteins. Proteins are vital parts of living organisms, with many functions such as the formation of structural fibers of muscle tissue, enzymatic digestion of food, or synthesis and replication of DNA. In ...

studies showed that ''M. jannaschii'' contains a large number of inteins: 19 were discovered by one study. Many novel metabolic pathways have been worked out in ''M. jannaschii'', including the pathways for synthesis of many methanogenic cofactors, riboflavin, and novel amino acid synthesis pathways. Many information processing pathways have also been studied in this organism, such as an archaeal-specific

DNA polymerase A DNA polymerase is a member of a family of enzymes that catalyze the synthesis of DNA molecules from nucleoside triphosphates, the molecular precursors of DNA. These enzymes are essential for DNA replication and usually work in groups to create ...

family. Information about single-pass transmembrane proteins from ''M. jannaschii'' was compiled in

Membranome database Membranome database provides structural and functional information about more than 6000 single-pass (bitopic) transmembrane proteins from ''Homo sapiens'', ''Arabidopsis thaliana'', ''Dictyostelium discoideum'', ''Saccharomyces cerevisiae'', '' ...

References

External links