Remarkable Conservation of Translation Initiation Factors: IF1/eIF1A and IF2/eIF5B are Universally Distributed Phylogenetic Markers

Abstract

Initiation of protein biosynthesis is an essential process occurring in cells throughout the three phylogenetic domains, Bacteria, Archaea, and Eucarya. IF1/eIF1A and IF2/eIF5B, two conserved translation initiation factors are involved in this important step of protein biosynthesis. The essentiality, universal distribution, conservation, and interspecies functional homology of both factors are a unique combination of properties ideal for molecular phylogenetic studies as demonstrated by the extensively compared SSU rRNAs. Here, we assess the use of IF1/eIF1A and IF2/eIF5B in universal and partial phylogenetic studies by comparison of sequence information from species within all three phylogenetic domains and among closely related strains of Haemophilus parainfluenzae. We conclude that the amino acid sequence of IF1/eIF1A-IF2/eIF5B is a universal phylogenetic marker and that the nucleotide sequence of the IF2/eIF5B G-domain is more credible than SSU rRNA for the construction of partial phylogenies among closely related species and strains. Because of these two application levels, IF1/eIF1A-IF2/eIF5B is a phylogenetic "dual level" marker.

Evolutionary and genetic analyses of mitochondrial translation initiation factors identify the missing mitochondrial IF3 in S. cerevisiae

“…Given all its crucial functions, it is unsurprising that IF1 is universal in bacteria, archaea (aIF1A) and the eukaryotic cytoplasm (eIF1A), as well as eukaryotic plastids (Figure 1) (72,73). However, it is not present in mitochondria, where mIF2 and mIF3 are able to function in in vitro IC formation without a mIF1 (Figure 1), (19).…”

Distinct Steps of Neural Induction Revealed by Asterix, Obelix and TrkC, Genes Induced by Different Signals from the Organizer

“…The region of greatest conservation between eukaryotic (eIF1A) and the shorter prokaryotic (IF1) translation initiation factors [49]–[51] encompasses the oligonucleotide/oligosaccharide-binding (OB) fold, which in human eIF1A is responsible for binding and scanning the mRNA [40], [52]. Different oligonucleotide- and oligosaccharide-binding proteins share this OB fold motif [53], comprising a five-stranded β-sheet, coiled to form a closed β-barrel, which has been described as a “five-stranded Greek key β barrel” [54], with strands proceeding from the amino- to the carboxy-terminus.…”

Established and Emerging Regulatory Roles of Eukaryotic Translation Initiation Factor 5B (eIF5B)

“…Interaction of eIF5B With eIF1A for Ribosome Recruitment eIF1A is one of the earliest discovered interacting partners of eIF5B. Similar to eIF5B, eIF1A is considered to be a universal translational factor (Sorensen et al, 2001). The interaction between these two initiation factors is thought to be important for eIF5B recruitment and mediating the joining of the large and small ribosomal subunits (Fringer et al, 2007).…”