A circularly permuted subfamily of the Ras GTPases.
Human HSR1 is localized to the human MHC class I region and is highly homologous to a putative GTP-binding protein, MMR1 from mouse. These proteins represent a new subfamily of GTP-binding proteins that has only eukaryote members. This subfamily shows a circular permutation of the GTPase signature motifs so that the C-terminal strands 5, 6, and 7 (strand 6 contains the G4 box with sequence NKXD) are relocated to the N-terminus.
Jiyao W et al.(2023). "The conserved domain database in 2023.",