D
IPR000795

Translational (tr)-type GTP-binding domain

InterPro entry
Short nameT_Tr_GTP-bd_dom
Overlapping
homologous
superfamilies
 
domain relationships

Description

Translational GTPases (trGTPases) are a family of proteins in which GTPase activity is stimulated by the large ribosomal subunit. This family includes translation initiation, elongation, and release factors and contains four subfamilies that are widespread, if not ubiquitous, in all three superkingdoms
[1]
. The trGTPase family members include bacteria elongation factors, EFTu, EFG, and the initiation factor, IF2, and their archaeal homologues, the EF1, EF2, aeIF5b and aeIF2. They all contain two homologous N-terminal domains: a GTPase or G-domain, followed by an OB-domain. These translational proteins' G-domains are both structurally and functionally related to a larger family of GTPase G proteins
[1]
. This entry represents the G-domain of the trGTPases.

The basic topology of the tr-type G domain consists of a six-stranded central β-sheet surrounded by five α-helices. Helices α2, α3 and α4 are on one side of the sheet, whereas α1 and α5 are on the other
[2]
. GTP is bound by the CTF-type G domain in a way common for G domains involving five conserved sequence motifs termed G1-G5. The base is in contact with the NKxD (G4) and SAx (G5) motifs, and the phosphates of the nucleotide are stabilised by main- and side-chain interactions with the P loop GxxxxGKT (G1). The most severe conformational changes are observed for the two switch regions which contain the xT/Sx (G2) and DxxG (G3) motifs that function as sensors for the presence of the gamma-phosphate. A Mg(2+) ion is coordinated by six oxygen ligands with octahedral coordination geometry; two of the ligands are water molecules, two come from the beta- and gamma-phosphates, and two are provided by the side chains of G1 and G2 threonines
[3]
.

References

1.Classification and evolution of P-loop GTPases and related ATPases. Leipe DD, Wolf YI, Koonin EV, Aravind L. J. Mol. Biol. 317, 41-72, (2002). View articlePMID: 11916378

2.Selenocysteine tRNA-specific elongation factor SelB is a structural chimaera of elongation and initiation factors. Leibundgut M, Frick C, Thanbichler M, Bock A, Ban N. EMBO J. 24, 11-22, (2005). View articlePMID: 15616587

3.eIF5B employs a novel domain release mechanism to catalyze ribosomal subunit joining. Kuhle B, Ficner R. EMBO J. 33, 1177-91, (2014). View articlePMID: 24686316

Further reading

4. Function of polypeptide chain release factor RF-3 in Escherichia coli. RF-3 action in termination is predominantly at UGA-containing stop signals. Grentzmann G, Brechemier-Baey D, Heurgue-Hamard V, Buckingham RH. J. Biol. Chem. 270, 10595-600, (1995). View articlePMID: 7737996

5. A conserved amino acid sequence around Arg-68 of Artemia elongation factor 1 alpha is involved in the binding of guanine nucleotides and aminoacyl transfer RNAs. Moller W, Schipper A, Amons R. Biochimie 69, 983-9, (1987). View articlePMID: 3126836

6. Identification of a novel translation factor necessary for the incorporation of selenocysteine into protein. Forchhammer K, Leinfelder W, Bock A. Nature 342, 453-6, (1989). View articlePMID: 2531290

7. Isolation and characterization of the rat chromosomal gene for a polypeptide (pS1) antigenically related to statin. Ann DK, Moutsatsos IK, Nakamura T, Lin HH, Mao PL, Lee MJ, Chin S, Liem RK, Wang E. J. Biol. Chem. 266, 10429-37, (1991). View articlePMID: 1709933

8. The products of the SUP45 (eRF1) and SUP35 genes interact to mediate translation termination in Saccharomyces cerevisiae. Stansfield I, Jones KM, Kushnirov VV, Dagkesamanskaya AR, Poznyakovski AI, Paushkin SV, Nierras CR, Cox BS, Ter-Avanesyan MD, Tuite MF. EMBO J. 14, 4365-73, (1995). View articlePMID: 7556078

9. The translation machinery and 70 kd heat shock protein cooperate in protein synthesis. Nelson RJ, Ziegelhoffer T, Nicolet C, Werner-Washburne M, Craig EA. Cell 71, 97-105, (1992). View articlePMID: 1394434

GO terms

biological process

  • None

cellular component

  • None

Cross References

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