This domain contains a P-loop motif, also found in several other families such as PF00071 PF00025 and PF00063. Elongation factor Tu consists of three structural domains, this plus two C-terminal beta barrel domains.
The translational GTPases are the 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 [PUBMED:11916378].