eEF-1 are two
eukaryotic elongation factor
Elongation factors are a set of proteins that function at the ribosome, during protein synthesis, to facilitate translation (genetics), translational elongation from the formation of the first to the last peptide bond of a growing polypeptide. ...
s. It forms two complexes, the
EF-Tu
EF-Tu (elongation factor thermo unstable) is a prokaryotic elongation factor responsible for catalyzing the binding of an aminoacyl-tRNA (aa-tRNA) to the ribosome. It is a G-protein, and facilitates the selection and binding of an aa-tRNA to th ...
homolog EF-1A and the
EF-Ts
EF-Ts (elongation factor thermo stable) is one of the prokaryotic elongation factors. It is found in human mitochrondria as TSFM. It is similar to eukaryotic EF-1B.
EF-Ts serves as the guanine nucleotide exchange factor for EF-Tu (elongation ...
homolog EF-1B, the former's guanide exchange factor.
Both are also found in
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 ...
.
Structure
The nomenclature for the eEF-1 subunits have somewhat shifted around circa 2001, as it was recognized that the EF-1A and EF-1B complexes are to some extent independent of each other.
[ Components as currently recognized and named include:][ eEF1A also binds ]actin
Actin is a family of globular multi-functional proteins that form microfilaments in the cytoskeleton, and the thin filaments in muscle fibrils. It is found in essentially all eukaryotic cells, where it may be present at a concentration of over ...
.[
]
Other species
Various species of green algae
The green algae (singular: green alga) are a group consisting of the Prasinodermophyta and its unnamed sister which contains the Chlorophyta and Charophyta/Streptophyta. The land plants (Embryophytes) have emerged deep in the Charophyte alga as ...
, red algae
Red algae, or Rhodophyta (, ; ), are one of the oldest groups of eukaryotic algae. The Rhodophyta also comprises one of the largest phyla of algae, containing over 7,000 currently recognized species with taxonomic revisions ongoing. The majority ...
, chromalveolate
Chromalveolata was a eukaryote supergroup present in a major classification of 2005, then regarded as one of the six major groups within the eukaryotes.
It was a refinement of the kingdom Chromista, first proposed by Thomas Cavalier-Smith in 1 ...
s, and fungi
A fungus ( : fungi or funguses) is any member of the group of eukaryotic organisms that includes microorganisms such as yeasts and molds, as well as the more familiar mushrooms. These organisms are classified as a kingdom, separately from ...
lack the EF-1α gene but instead possess a related gene called EFL (elongation factor-like). Although its function has not been studied in depth, it appears to be similar to EF-1α.
, only two organisms are known to have both EF-1α and EFL: the fungus '' Basidiobolus'' and the diatom ''Thalassiosira
''Thalassiosira'' is a genus of centric diatoms, comprising over 100 marine and freshwater species. It is a diverse group of photosynthetic eukaryotes that make up a vital part of marine and freshwater ecosystems, in which they are key primary pr ...
''. The evolutionary history of EFL is unclear. It may have arisen one or more times followed by loss of EFL or EF-1α. The presence in three diverse eukaryotic groups (fungi, chromalveolates, and archaeplastida
The Archaeplastida (or kingdom Plantae ''sensu lato'' "in a broad sense"; pronounced /ɑːrkɪ'plastɪdə/) are a major group of eukaryotes, comprising the photoautotrophic red algae (Rhodophyta), green algae, land plants, and the minor group ...
) is supposed to be the result of two or more horizontal gene transfer
Horizontal gene transfer (HGT) or lateral gene transfer (LGT) is the movement of genetic material between Unicellular organism, unicellular and/or multicellular organisms other than by the ("vertical") transmission of DNA from parent to offsprin ...
events, according to a 2009 review. A 2013 report finds 11 more species with both genes, and provided an alternative hypothesis that an ancestor eukaryote may have both genes. In all known organisms where both genes are present, EF-1α tends to be transcriptionally repressed. If the hypothesis holds true, scientists would expect to find an organism that has a repressed EFL and a fully-functioning EF-1α.
See also
*Eukaryotic translation
Eukaryotic translation is the biological process by which messenger RNA is translated into proteins in eukaryotes. It consists of four phases: gene translation, elongation, termination, and recapping.
Initiation
Translation initiation is the pr ...
References
External links
*
{{GTPases
Protein biosynthesis
Eukaryote genes