protein-synthesizing GTPase;
elongation factor (EF);
initiation factor (IF);
peptide-release or termination factor

Hydrolases;
Acting on acid anhydrides;
Acting on GTP to facilitate cellular and subcellular movement

GTP phosphohydrolase (mRNA-translation-assisting)

GTP + H2O = GDP + phosphate [RN:R00335]

R00335

GTP [CPD:C00044];
H2O [CPD:C00001]

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 hydrolyses it in prokaryotes. In eukaryotes, it is eIF-2 (150 kDa) that binds GTP. In the elongation phase, the GTP-hydrolysing proteins are the EF-Tu polypeptide of the prokaryotic transfer factor (43 kDa), the eukaryotic elongation factor EF-1alpha (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-1alpha catalyse binding of aminoacyl-tRNA to the ribosomal A-site, while EF-G and EF-2 catalyse 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.

1  [PMID:6566615]

Kurzchalia TV, Bommer UA, Babkina GT, Karpova GG.

GTP interacts with the gamma-subunit of eukaryotic initiation factor eIF-2.

FEBS. Lett. 175 (1984) 313-6.

Rattus norvegicus [GN:rno]

2  [PMID:8722024]

Kisselev LL, Frolova LYu.

Termination of translation in eukaryotes.

Biochem. Cell. Biol. 73 (1995) 1079-86.

Homo sapiens [GN:hsa], Xenopus laevis [GN:xla]

3  [PMID:8985244]

Rodnina MV, Savelsbergh A, Katunin VI, Wintermeyer W.

Hydrolysis of GTP by elongation factor G drives tRNA movement on the ribosome.

Nature. 385 (1997) 37-41.

Thermus thermophilus, Escherichia coli [GN:eco]

4  [PMID:9233821]

Freistroffer DV, Pavlov MY, MacDougall J, Buckingham RH, Ehrenberg M.

Release factor RF3 in E.coli accelerates the dissociation of release factors RF1 and RF2 from the ribosome in a GTP-dependent manner.

EMBO. J. 16 (1997) 4126-33.

Escherichia coli [GN:eco]

5  [PMID:9838020]

Krab IM, Parmeggiani A.

EF-Tu, a GTPase odyssey.

Biochim. Biophys. Acta. 1443 (1998) 1-22.

Thermus thermophilus, Thermus aquaticus, Salmonella typhimurium