Elongation factor

Source: Wikipedia, the free encyclopedia.
Not to be confused with
Relative elongation
.
"EF2" and "EF-2" redirect here. For the tornado intensity rating, see Enhanced Fujita scale § Parameters.
Ternary complex of EF-Tu (blue), tRNA (red) and GTP (yellow). Taken from PDB Molecule of the Month Elongation factors, September 2006.

Elongation factors are a set of proteins that function at the

polypeptide. Most common elongation factors in prokaryotes are EF-Tu, EF-Ts, EF-G.[1] Bacteria and eukaryotes use elongation factors that are largely homologous to each other, but with distinct structures and different research nomenclatures.[2]

Elongation is the most rapid step in translation.

eukaryotes the rate is about two amino acids per second (about 6 nucleotides read per second).[citation needed] Elongation factors play a role in orchestrating the events of this process, and in ensuring the high accuracy translation at these speeds.[citation needed
]

Nomenclature of homologous EFs

Elongation factors
Bacterial Eukaryotic/Archaeal Function
EF-Tu eEF-1A (α)[2] mediates the entry of the aminoacyl
tRNA into a free site of the ribosome.[4]
EF-Ts eEF-1B (βγ)[2] serves as the guanine nucleotide exchange factor for EF-Tu, catalyzing the release of GDP from EF-Tu.[2]
EF-G
eEF-2
 catalyzes the translocation of the tRNA and mRNA down the ribosome at the end of each round of polypeptide elongation. Causes large conformation changes.[5]
EF-P
eIF-5A
 possibly stimulates formation of peptide bonds and resolves stalls.[6]
EF-4 (None) Proofreading
Note that EIF5A, the archaeal and eukaryotic homolog to EF-P, was named as an initiation factor but now considered an elongation factor as well.[6]

In addition to their cytoplasmic machinery, eukaryotic mitochondria and plastids have their own translation machinery, each with their own set of bacterial-type elongation factors.[7][8] In humans, they include TUFM, TSFM, GFM1, GFM2, GUF1; the nominal release factor MTRFR may also play a role in elongation.[9]

In bacteria, selenocysteinyl-tRNA requires a special elongation factor SelB (P14081) related to EF-Tu. A few homologs are also found in archaea, but the functions are unknown.[10]

As a target

Elongation factors are targets for the toxins of some pathogens. For instance,

exotoxin A inactivates EF-2.[11]

References

  1. ISBN 9780122270802
    .
  2. ^
    PMID 22555874
    .
  3. PMID 28480640
    .
  4. PMID 1573997
    .
  5. S2CID 4795260
    .
  6. ^
    S2CID 25447826
    .
  7. PMID 17683199
    .
  8. PMID 21097998
    .
  9. ^ "KEGG DISEASE: Combined oxidative phosphorylation deficiency". www.genome.jp.
  10. PMID 21255425
    .
  11. PMID 6326138
    .

Further reading

External links
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