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208  structures 8926  species 0  interactions 21771  sequences 186  architectures

Family: EFG_IV (PF03764)

Summary: Elongation factor G, domain IV

Pfam includes annotations and additional family information from a range of different sources. These sources can be accessed via the tabs below.

This is the Wikipedia entry entitled "EF-G". More...

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This tab holds the annotation information that is stored in the Pfam database. As we move to using Wikipedia as our main source of annotation, the contents of this tab will be gradually replaced by the Wikipedia tab.

Elongation factor G, domain IV Provide feedback

This domain is found in elongation factor G, elongation factor 2 and some tetracycline resistance proteins and adopts a ribosomal protein S5 domain 2-like fold.

Internal database links

External database links

This tab holds annotation information from the InterPro database.

InterPro entry IPR005517

Translation elongation factors are responsible for two main processes during protein synthesis on the ribosome [ PUBMED:12762045 , PUBMED:15922593 , PUBMED:12932732 ]. EF1A (or EF-Tu) is responsible for the selection and binding of the cognate aminoacyl-tRNA to the A-site (acceptor site) of the ribosome. EF2 (or EF-G) is responsible for the translocation of the peptidyl-tRNA from the A-site to the P-site (peptidyl-tRNA site) of the ribosome, thereby freeing the A-site for the next aminoacyl-tRNA to bind. Elongation factors are responsible for achieving accuracy of translation and both EF1A and EF2 are remarkably conserved throughout evolution.

Elongation factor EF2 (EF-G) is a G-protein. It brings about the translocation of peptidyl-tRNA and mRNA through a ratchet-like mechanism: the binding of GTP-EF2 to the ribosome causes a counter-clockwise rotation in the small ribosomal subunit; the hydrolysis of GTP to GDP by EF2 and the subsequent release of EF2 causes a clockwise rotation of the small subunit back to the starting position [ PUBMED:12762009 , PUBMED:12762047 ]. This twisting action destabilises tRNA-ribosome interactions, freeing the tRNA to translocate along the ribosome upon GTP-hydrolysis by EF2. EF2 binding also affects the entry and exit channel openings for the mRNA, widening it when bound to enable the mRNA to translocate along the ribosome.

EF2 has five domains. This entry represents domain IV found in EF2 (or EF-G) of both prokaryotes and eukaryotes. The EF2-GTP-ribosome complex undergoes extensive structural rearrangement for tRNA-mRNA movement to occur. Domain IV, which extends from the 'body' of the EF2 molecule much like a lever arm, facilitates the movement of peptidyl-tRNA from the A to the P site, being critical for the structural transition to take place [ PUBMED:25288752 ].

Included in this entry is a domain of mitochondrial Elongation factor G1 (mtEFG1) proteins that is homologous to domain IV of EF-G. Eukaryotic cells harbor 2 protein synthesis systems: one localized in the cytoplasm, the other in the mitochondria. Most factors regulating mitochondrial protein synthesis are encoded by nuclear genes, translated in the cytoplasm, and then transported to the mitochondria. The eukaryotic system of elongation factor (EF) components is more complex than that in prokaryotes, with both cytoplasmic and mitochondrial elongation factors and multiple isoforms being expressed in certain species. During the process of peptide synthesis and tRNA site changes, the ribosome is moved along the mRNA a distance equal to one codon with the addition of each amino acid. In bacteria this translocation step is catalyzed by EF-G_GTP, which is hydrolyzed to provide the required energy. Thus, this action releases the uncharged tRNA from the P site and transfers the newly formed peptidyl-tRNA from the A site to the P site. Eukaryotic mtEFG1 proteins show significant homology to bacterial EF-Gs. Mutants in yeast mtEFG1 have impaired mitochondrial protein synthesis, respiratory defects and a tendency to lose mitochondrial DNA [ PUBMED:11735030 , PUBMED:1935960 , PUBMED:15922593 , PUBMED:1602493 , PUBMED:8159735 , PUBMED:10837219 , PUBMED:12471894 , PUBMED:16213500 , PUBMED:12932345 ].

Gene Ontology

The mapping between Pfam and Gene Ontology is provided by InterPro. If you use this data please cite InterPro.

Domain organisation

Below is a listing of the unique domain organisations or architectures in which this domain is found. More...

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Pfam Clan

This family is a member of clan S5 (CL0329), which has the following description:

This superfamily contains a wide range of families that possess a structure similar to the second domain of ribosomal S5 protein.

The clan contains the following 18 members:

ChlI DNA_gyraseB DNA_mis_repair EFG_IV Fae GalKase_gal_bdg GHMP_kinases_N IGPD Lon_C LpxC Morc6_S5 Ribonuclease_P Ribosomal_S5_C Ribosomal_S9 RNase_PH Topo-VIb_trans UPF0029 Xol-1_N


We store a range of different sequence alignments for families. As well as the seed alignment from which the family is built, we provide the full alignment, generated by searching the sequence database (reference proteomes) using the family HMM. We also generate alignments using four representative proteomes (RP) sets and the UniProtKB sequence database. More...

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We make a range of alignments for each Pfam-A family. You can see a description of each above. You can view these alignments in various ways but please note that some types of alignment are never generated while others may not be available for all families, most commonly because the alignments are too large to handle.

Representative proteomes UniProt
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PP/heatmap 1            

1Cannot generate PP/Heatmap alignments for seeds; no PP data available

Key: ✓ available, x not generated, not available.

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Representative proteomes UniProt

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We make all of our alignments available in Stockholm format. You can download them here as raw, plain text files or as gzip-compressed files.

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You can also download a FASTA format file containing the full-length sequences for all sequences in the full alignment.

HMM logo

HMM logos is one way of visualising profile HMMs. Logos provide a quick overview of the properties of an HMM in a graphical form. You can see a more detailed description of HMM logos and find out how you can interpret them here. More...


This page displays the phylogenetic tree for this family's seed alignment. We use FastTree to calculate neighbour join trees with a local bootstrap based on 100 resamples (shown next to the tree nodes). FastTree calculates approximately-maximum-likelihood phylogenetic trees from our seed alignment.

Note: You can also download the data file for the tree.

Curation and family details

This section shows the detailed information about the Pfam family. You can see the definitions of many of the terms in this section in the glossary and a fuller explanation of the scoring system that we use in the scores section of the help pages.

Curation View help on the curation process

Seed source: Pfam-B_40 (release 2.1)
Previous IDs: none
Type: Domain
Sequence Ontology: SO:0000417
Author: Bateman A , Griffiths-Jones SR
Number in seed: 64
Number in full: 21771
Average length of the domain: 118.7 aa
Average identity of full alignment: 32 %
Average coverage of the sequence by the domain: 16.22 %

HMM information View help on HMM parameters

HMM build commands:
build method: hmmbuild -o /dev/null HMM SEED
search method: hmmsearch -Z 61295632 -E 1000 --cpu 4 HMM pfamseq
Model details:
Parameter Sequence Domain
Gathering cut-off 24.0 24.0
Trusted cut-off 24.0 24.0
Noise cut-off 23.9 23.9
Model length: 121
Family (HMM) version: 21
Download: download the raw HMM for this family

Species distribution

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Colour assignments

Archea Archea Eukaryota Eukaryota
Bacteria Bacteria Other sequences Other sequences
Viruses Viruses Unclassified Unclassified
Viroids Viroids Unclassified sequence Unclassified sequence


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This visualisation provides a simple graphical representation of the distribution of this family across species. You can find the original interactive tree in the adjacent tab. More...

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The tree shows the occurrence of this domain across different species. More...


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For those sequences which have a structure in the Protein DataBank, we use the mapping between UniProt, PDB and Pfam coordinate systems from the PDBe group, to allow us to map Pfam domains onto UniProt sequences and three-dimensional protein structures. The table below shows the structures on which the EFG_IV domain has been found. There are 208 instances of this domain found in the PDB. Note that there may be multiple copies of the domain in a single PDB structure, since many structures contain multiple copies of the same protein sequence.

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AlphaFold Structure Predictions

The list of proteins below match this family and have AlphaFold predicted structures. Click on the protein accession to view the predicted structure.

Protein Predicted structure External Information
A0A044RZ79 View 3D Structure Click here
A0A044UJF6 View 3D Structure Click here
A0A044V0R1 View 3D Structure Click here
A0A077Z0M0 View 3D Structure Click here
A0A077Z7P3 View 3D Structure Click here
A0A077ZBD6 View 3D Structure Click here
A0A077ZHL8 View 3D Structure Click here
A0A077ZL28 View 3D Structure Click here
A0A096QR66 View 3D Structure Click here
A0A0D2DM09 View 3D Structure Click here
A0A0D2FB79 View 3D Structure Click here
A0A0D2H021 View 3D Structure Click here
A0A0H3GWM9 View 3D Structure Click here
A0A0H3H0I2 View 3D Structure Click here
A0A0H5S2V5 View 3D Structure Click here
A0A0H5S693 View 3D Structure Click here
A0A0K0DVK5 View 3D Structure Click here
A0A0K0DXW6 View 3D Structure Click here
A0A0K0E0F1 View 3D Structure Click here
A0A0K0EMH4 View 3D Structure Click here
A0A0N4U760 View 3D Structure Click here
A0A0N4UBG7 View 3D Structure Click here
A0A158N811 View 3D Structure Click here
A0A158Q604 View 3D Structure Click here
A0A175VPY2 View 3D Structure Click here
A0A175VSR7 View 3D Structure Click here
A0A175VW71 View 3D Structure Click here
A0A175VWA9 View 3D Structure Click here
A0A175W8E2 View 3D Structure Click here
A0A1C1CL36 View 3D Structure Click here
A0A1C1CY30 View 3D Structure Click here
A0A1C1D0Q8 View 3D Structure Click here
A0A1D6E4M0 View 3D Structure Click here
A0A1D6I3L1 View 3D Structure Click here
A0A1D6LAW0 View 3D Structure Click here
A0A1D6P3B9 View 3D Structure Click here
A0A1D8PH71 View 3D Structure Click here
A0A1U7F448 View 3D Structure Click here
A0A286Y8X9 View 3D Structure Click here
A0A3P7DJS0 View 3D Structure Click here