This domain is part of the G domain found at the C-terminus of pfam01926 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. 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.