Archaeal initiation factors

Archaeal initiation factors are proteins that are used during the translation step of protein synthesis in archaea. The principal functions these proteins perform include ribosome RNA/mRNA recognition, delivery of the initiator Met-tRNAiMet, methionine bound tRNAi, to the 40s ribosome, and proofreading of the initiation complex[1].

Conservation of archaeal initiation factors

Of the three domains of life, archaea, eukaryotes, and bacteria, the number of archaeal TIFs is somewhere between eukaryotes and bacteria; eukaryotes have the largest number of TIFs, and bacteria, having streamlined the process, have only three TIFs[1]. Not only are archaeal TIF numbers between that of bacteria and eukaryote numbers, but archaeal initiation factors are seen to have both traits of eukaryotic and prokaryotic intiation factors[2]. Two core TIFs, IF1/IF1A and IF2/IF5B are conserved across the three domains of life[1]. There is also a semi-universal TIF found in all archaea and eukaryote called IF1/SUI1, but only in certain bacterial species (YciH). In archeaes and eukaryotes, these TIFs help correct the identification of the intiation codon, while its function is unknown in bacteria[1]. Just between eukaryote and archaea, a/eIF2 (trimer) and aIF6 in archaeas are conserved in eukaryotes as eIF2(trimer) and eIF6 TIFs[1].

aIF1

AIF1 plays a role in occupying the ribosomal A site, helping the unambiguous placement of tRNAi in the P site of in the large ribosomal subunit[1].

aIF2

The main function of archaeal IF2 is to join the ribosomal subunits (small and large) to form the complete single (monomeric) mRNA bound ribosome unit in the late stages of initiation[1].

a/eIF2 (trimer)

The a/eIF2 binds to the 40S small subunit of the ribosome to help guide the start translation of mRNA into proteins[3].

References

  1. 1 2 3 4 5 6 7 Evolution of the protein synthesis machinery and its regulation. Hernández, Greco,, Jagus, Rosemary,. Switzerland. ISBN 9783319394688. OCLC 956539514.
  2. ↑ Dmitriev, Sergey E.; Stolboushkina, Elena A.; Terenin, Ilya M.; Andreev, Dmitri E.; Garber, Maria B.; Shatsky, Ivan N. "Archaeal Translation Initiation Factor aIF2 Can Substitute for Eukaryotic eIF2 in Ribosomal Scanning during Mammalian 48S Complex Formation". Journal of Molecular Biology. 413 (1): 106–114. doi:10.1016/j.jmb.2011.08.026.
  3. ↑ Gogoi, Prerana; Kanaujia, Shankar Prasad. "Archaeal and eukaryal translation initiation factor 1 differ in their RNA interacting loops". FEBS Letters. doi:10.1002/1873-3468.13044.
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