This group represents GTPases that belong to MMR1/HSR1 GTP-binding protein family, MTG1 subfamily. This entry includes Mitochondrial GTPase MTG1 which is required for mitochondrial translation. It is probably involved in assembly of the large ribosomal subunit []. This family also includes Ribosome biogenesis GTPase A, an essential protein for a late step of 50S ribosomal subunit assembly [, ].