This model represents examples from the eukaryotic cytosol of the signal recognition particle protein component, SRP54. This GTP-binding protein is a component of the eukaryotic signal recognition particle, along with several other protein subunits and a 7S RNA. Some species, including Arabidopsis, have several closely related forms. The extreme C-terminal region is glycine-rich and lower in complexity, poorly conserved between species, and excluded from this model.