CATH Classification

Domain Context

CATH Clusters

Superfamily P-loop containing nucleotide triphosphate hydrolases
Functional Family Eukaryotic translation initiation factor 5B

Enzyme Information

3.6.5.3
Protein-synthesizing GTPase.
based on mapping to UniProt P39730
GTP + H(2)O = GDP + phosphate.
-!- This enzyme comprises a family of proteins involved in prokaryotic as well as eukaryotic protein synthesis. -!- In the initiation factor complex, it is IF-2b (98 kDa) that binds GTP and subsequently hydrolyzes it in prokaryotes. -!- In eukaryotes, it is eIF-2 (150 kDa) that binds GTP. -!- In the elongation phase, the GTP-hydrolyzing proteins are the EF-Tu polypeptide of the prokaryotic transfer factor (43 kDa), the eukaryotic elongation factor EF-1-alpha (53 kDa), the prokaryotic EF-G (77 kDa), the eukaryotic EF-2 (70-110 kDa) and the signal recognition particle that play a role in endoplasmic reticulum protein synthesis (325 kDa). -!- EF-Tu and EF-1-alpha catalyze binding of aminoacyl-tRNA to the ribosomal A-site, while EF-G and EF-2 catalyze the translocation of peptidyl-tRNA from the A-site to the P-site. -!- GTPase activity is also involved in polypeptide release from the ribosome with the aid of the pRFs and eRFs. -!- Formerly EC 3.6.1.48.

UniProtKB Entries (1)

P39730
IF2P_YEAST
Saccharomyces cerevisiae S288C
Eukaryotic translation initiation factor 5B

PDB Structure

PDB 4NCF
External Links
Method X-RAY DIFFRACTION
Organism
Primary Citation
eIF5B employs a novel domain release mechanism to catalyze ribosomal subunit joining.
Kuhle, B., Ficner, R.
Embo J.