This domain is part of the G domain found at the C-terminus of Pfam:PF01926 in archaeal and eukaryotic GTP-binding proteins. Members of this entry form a subfamily within the Obg family of GTPases and includes YGR210 from yeasts and its homologues from archaea [1]. This domain seems to be necessary for the complete activity of the protein for binding of both adenine and guanine nucleotides, with a preference for guanine nucleotides. This domain contains the NKxD motif, known as the G4 motif [1].

1: Human OLA1 defines an ATPase subfamily in the Obg family of GTP-binding proteins. Koller-Eichhorn R, Marquardt T, Gail R, Wittinghofer A, Kostrewa D, Kutay U, Kambach C; J Biol Chem. 2007;282:19928-19937. PMID:17430889