Elongation factor P
EF-P (elongation factor P) is an essential protein that in bacteria stimulates the formation of the first peptide bonds in protein synthesis. Studies show that EF-P prevents ribosomes from stalling during the synthesis of proteins containing consecutive prolines. EF-P binds to a site located between the binding site for the peptidyl tRNA (P site) and the exiting tRNA (E site). It spans both ribosomal subunits with its amino-terminal domain positioned adjacent to the aminoacyl acceptor stem and its carboxyl-terminal domain positioned next to the anticodon stem-loop of the P site-bound initiator tRNA. The EF-P protein shape and size is very similar to a tRNA and interacts with the ribosome via the exit “E” site on the 30S subunit and the peptidyl-transferase center (PTC) of the 50S subunit. EF-P is a translation aspect of an unknown function, therefore It probably functions indirectly by altering the affinity of the ribosome for aminoacyl-tRNA, thus increasing their reactivity as acceptors for peptidyl transferase.
| Elongation factor P (EF-P) KOW-like domain | |||||||||
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crystal structure of translation initiation factor 5a from pyrococcus horikoshii | |||||||||
| Identifiers | |||||||||
| Symbol | EFP_N | ||||||||
| Pfam | PF08207 | ||||||||
| Pfam clan | CL0107 | ||||||||
| InterPro | IPR013185 | ||||||||
| PROSITE | PDOC00981 | ||||||||
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| Elongation factor P (EF-P) OB domain | |||||||||
|---|---|---|---|---|---|---|---|---|---|
crystal structure of translation elongation factor p from thermus thermophilus hb8 | |||||||||
| Identifiers | |||||||||
| Symbol | EFP | ||||||||
| Pfam | PF01132 | ||||||||
| Pfam clan | CL0021 | ||||||||
| InterPro | IPR001059 | ||||||||
| PROSITE | PDOC00981 | ||||||||
| CDD | cd04470 | ||||||||
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| Elongation factor P, C-terminal | |||||||||
|---|---|---|---|---|---|---|---|---|---|
crystal structure of translation elongation factor p from thermus thermophilus hb8 | |||||||||
| Identifiers | |||||||||
| Symbol | Elong-fact-P_C | ||||||||
| Pfam | PF09285 | ||||||||
| InterPro | IPR015365 | ||||||||
| SCOP2 | 1ueb / SCOPe / SUPFAM | ||||||||
| CDD | cd05794 | ||||||||
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EF-P consists of three domains:
- An N-terminal KOW-like domain
- A central OB domain, which forms an oligonucleotide-binding fold. It is not clear if this region is involved in binding nucleic acids
- A C-terminal domain which adopts an OB-fold, with five beta-strands forming a beta-barrel in a Greek-key topology
Eukaryotes and archaea lack EF-P. In these domains, a similar function is performed by the archaeo-eukaryotic initiation factor, a/eIF-5A, which exhibits some modest sequence and structural similarity with EF-P. There are, however, important differences between EF-p and eIF-5A. (a) EF-P has a structure similar to that of L-shaped tRNA and it contains three (I,II and III) β-barrel domains. In contrast, eIF-5A contains only two domains (C and N) with a corresponding size difference. (b) Moreover, as opposed to eIF-5A, which contains the non-proteinogenic amino acid hypusine that is essential for its activity, EF-P displays a diversity of post-transcriptional modifications at the analogous position (β-lysylation of lysine residue, rhamnosylation of arginine residue, or none at all).