Elongation factor

Function

Elongation factors (EF) facilitate translational elongation during the formation of peptide bonds in the ribosome.

• EF-selB is selenocysteine-specific EF. See SelB
  
• EF-Tu or EF 1-α (elongation factor thermo unstable) is a prokaryotic EF. EF-Tu contributes to translational accuracy. It catalyzes the addition of aminoacyl tRNA^[1].
  
• EF-Ts or EF 1-β (elongation factor thermo stable) catalyzes the release of GDP from EF-Tu.
  
• EF-G translocates the peptidyl tRNA from the A site to the P site while moving the mRNA through the ribosome.
  
• EF-SII helps RNA polymerase II to bypass blocks to elongation.
  
• EF-ELL2 enhances polyadenylation and exon skipping with the gene encoding the immunoglobulin heavy-chain complex.
  
• EF-GreA or GreB are cleavage factors allowing the resumption of elongation.
  
• EF-NusA recruits translesion DNA polymerases to gaps encountered during translation.
  
• EF-P alters the ribosome affinity to aminoacyl-tRNA.
  
• EF-1 γ acts during the delivery of aminoacyl tRNA to the ribosome.
  
• EF-2 promotes the translocation of the nascent protein chain from the A site to the P site on the ribosome^[2].
  
• EF-3 is a unique EF in fungi hence it provides an anti-fungal drug target. See HEAT Repeat
  
• EF Spt4, Spt5, Spt6 are conserved among eukaryotes. They modulate the chromatin structure.
  
• EF-CA150 is believed to play a role in coupling transcription and splicing.
  
• Elongin complex or SIII activates elongation by RNA polymerase II by suppressing transient pausing of the enzyme^[3]. The complex is composed of elongin A, B and C. Elongin A (EloA) is the active component of the complex. Elongin B and C (EloBC) are the regulatory subunits of it. Von Hippel-Landau tumor suppressor protein (VHL) binds to EloBC and inhibits transcriptional elongation.
  

Complex EF-Tu with EF-Ts is heterotetramer, or, more exactly heterodimer of homodimers (PDB entry 1efu).^[4]

3D structures of elongation factor

Elongation factor 3D structures