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 | |||||||||
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![]() 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 | |||||||||
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![]() 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 (elongation factor P) is an essential protein that in bacteria stimulates the formation of the first peptide bonds in protein synthesis. [1] [2] Studies show that EF-P prevents ribosomes from stalling during the synthesis of proteins containing consecutive prolines. [1] 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. [3] 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. [4] EF-P is a translation aspect of an unknown function, [1] therefore It probably functions indirectly by altering the affinity of the ribosome for aminoacyl-tRNA, thus increasing their reactivity as acceptors for peptidyl transferase.
EF-P consists of three domains:
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. [2] [6] 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. [2] (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). [7] [8]
In eubacteria, there are three groups of factors that promote protein synthesis: initiation factors, elongation factors and termination factors. [7] The elongation phase of translation is promoted by three universal elongation factors, EF-Tu, EF-Ts, and EF-G. [9] EF-P was discovered in 1975 by Glick and Ganoza, [10] as a factor that increased the yield of peptide bond formation between initiator fMet-tRNA(fMet) and a mimic of aa-tRNA, puromycin (Pmn). The low yield of product formation in absence of EF-P can be described by the loss of peptidyl-tRNA from the stalled ribosome. Thus, EF-P is not a necessary component of minimal in vitro translation system, however, the absence of EF-P can limit translation rate, increase antibiotic sensitivity, and slow growth.
To complete its function, EF-P enters paused ribosomes through the E-site and facilitates peptide bond formation through interactions with the P-site tRNA. [11] EF-P and eIF-5A both are essential for the synthesis of a subset of proteins containing proline stretches in all cells. [1]
It has been suggested that after binding of the initiator tRNA to the P/I site, it is correctly positioned to the P site by binding of EF-P to the E site. [12] Additionally, EF-P has been shown to assist in efficient translation of three or more consecutive proline residues. [13]
EF-P is a 21 kDa protein encoded by the efp gene. [9] EF-P consists of three β-barrel domains (I,II and III) and has a L shape tRNA structure. Domain II and III of EF-P are similar to each other. Despite the structural similarity of EF-P with tRNA, studies showed that EF-P does not bind to the ribosome at the classical tRNA binding site, but at the distinct position that is located between the P and E sites. [3]
Ribosomes are macromolecular machines, found within all cells, that perform biological protein synthesis. Ribosomes link amino acids together in the order specified by the codons of messenger RNA molecules to form polypeptide chains. Ribosomes consist of two major components: the small and large ribosomal subunits. Each subunit consists of one or more ribosomal RNA molecules and many ribosomal proteins. The ribosomes and associated molecules are also known as the translational apparatus.
In biology, translation is the process in living cells in which proteins are produced using RNA molecules as templates. The generated protein is a sequence of amino acids. This sequence is determined by the sequence of nucleotides in the RNA. The nucleotides are considered three at a time. Each such triple results in addition of one specific amino acid to the protein being generated. The matching from nucleotide triple to amino acid is called the genetic code. The translation is performed by a large complex of functional RNA and proteins called ribosomes. The entire process is called gene expression.
The peptidyl transferase center is an aminoacyltransferase ribozyme located in the large subunit of the ribosome. It forms peptide bonds between adjacent amino acids during the translation process of protein biosynthesis. It is also responsible for peptidyl-tRNA hydrolysis, allowing the release of the synthesized peptide chain at the end of translation. Peptidyl transferase activity is not mediated by any ribosomal proteins, but entirely by ribosomal RNA (rRNA). The peptidyl transferase center is a significant piece of evidence supporting the RNA World hypothesis.
Bacterial translation is the process by which messenger RNA is translated into proteins in bacteria.
Eukaryotic translation is the biological process by which messenger RNA is translated into proteins in eukaryotes. It consists of four phases: initiation, elongation, termination, and recapping.
A release factor is a protein that allows for the termination of translation by recognizing the termination codon or stop codon in an mRNA sequence. They are named so because they release new peptides from the ribosome.
Elongation factors are a set of proteins that function at the ribosome, during protein synthesis, to facilitate translational elongation from the formation of the first to the last peptide bond of a growing polypeptide. Most common elongation factors in prokaryotes are EF-Tu, EF-Ts, EF-G. Bacteria and eukaryotes use elongation factors that are largely homologous to each other, but with distinct structures and different research nomenclatures.
EF-Tu 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 the A-site of the ribosome. As a reflection of its crucial role in translation, EF-Tu is one of the most abundant and highly conserved proteins in prokaryotes. It is found in eukaryotic mitochondria as TUFM.
A bacterial initiation factor (IF) is a protein that stabilizes the initiation complex for polypeptide translation.
Eukaryotic translation termination factor1 (eRF1), also referred to as TB3-1 or SUP45L1, is a protein that is encoded by the ERF1 gene. In Eukaryotes, eRF1 is an essential protein involved in stop codon recognition in translation, termination of translation, and nonsense mediated mRNA decay via the SURF complex.
Elongation factor 4 (EF-4) is an elongation factor that is thought to back-translocate on the ribosome during the translation of RNA to proteins. It is found near-universally in bacteria and in eukaryotic endosymbiotic organelles including the mitochondria and the plastid. Responsible for proofreading during protein synthesis, EF-4 is a recent addition to the nomenclature of bacterial elongation factors.
50S is the larger subunit of the 70S ribosome of prokaryotes, i.e. bacteria and archaea. It is the site of inhibition for antibiotics such as macrolides, chloramphenicol, clindamycin, and the pleuromutilins. It includes the 5S ribosomal RNA and 23S ribosomal RNA.
The 23S rRNA is a 2,904 nucleotide long component of the large subunit (50S) of the bacterial/archean ribosome and makes up the peptidyl transferase center (PTC). The 23S rRNA is divided into six secondary structural domains titled I-VI, with the corresponding 5S rRNA being considered domain VII. The ribosomal peptidyl transferase activity resides in domain V of this rRNA, which is also the most common binding site for antibiotics that inhibit translation, making it a target for ribosomal engineering. A well-known member of this antibiotic class, chloramphenicol, acts by inhibiting peptide bond formation, with recent 3D-structural studies showing two different binding sites depending on the species of ribosome. Numerous mutations in domains of the 23S rRNA with Peptidyl transferase activity have resulted in antibiotic resistance. 23S rRNA genes typically have higher sequence variations, including insertions and/or deletions, compared to other rRNAs.
Eukaryotic translation initiation factor 5A-1 is a protein that in humans is encoded by the EIF5A gene.
EF-G is a prokaryotic elongation factor involved in mRNA translation. As a GTPase, EF-G catalyzes the movement (translocation) of transfer RNA (tRNA) and messenger RNA (mRNA) through the ribosome.
A protein synthesis inhibitor is a compound that stops or slows the growth or proliferation of cells by disrupting the processes that lead directly to the generation of new proteins.
EF-Ts is one of the prokaryotic elongation factors. It is found in human mitochondria as TSFM. It is similar to eukaryotic EF-1B.
The P-site is the second binding site for tRNA in the ribosome. The other two sites are the A-site (aminoacyl), which is the first binding site in the ribosome, and the E-site (exit), the third. During protein translation, the P-site holds the tRNA which is linked to the growing polypeptide chain. When a stop codon is reached, the peptidyl-tRNA bond of the tRNA located in the P-site is cleaved releasing the newly synthesized protein. During the translocation step of the elongation phase, the mRNA is advanced by one codon, coupled to movement of the tRNAs from the ribosomal A to P and P to E sites, catalyzed by elongation factor EF-G.
In molecular biology, VAR1 protein domain, otherwise known as variant protein 1, is a ribosomal protein that forms part of the small ribosomal subunit in yeast mitochondria. Mitochondria possess their own ribosomes responsible for the synthesis of a small number of proteins encoded by the mitochondrial genome. VAR1 is the only protein in the yeast mitochondrial ribosome to be encoded in the mitochondria - the remaining approximately 80 ribosomal proteins are encoded in the nucleus. VAR1 along with 15S rRNA are necessary for the formation of mature 37S subunits.
Ribosomal L28e protein family is a family of evolutionarily related proteins. Members include 60S ribosomal protein L28.