GTPase that may function in mitochondrial ribosome assembly (Probable). In contrast to other GTP-binding proteins, this family is characterized by a circular permutation of the GTPase motifs described by a G4-G1-G3 pattern. The DARXP motif is also sometime designated as G6 region. Belongs to the TRAFAC class YlqF/YawG GTPase family. MTG1 subfamily.