This is a family of short mitochondrial ribosomal proteins, less than 200 amino acids long. that are highly conserved from worms to humans. The structure has previously been referred to as MRP-S18 but the current numbering fits the preferred nomenclature from these authors.

1: The small subunit of the mammalian mitochondrial ribosome. Identification of the full complement of ribosomal proteins present. Cavdar Koc E, Burkhart W, Blackburn K, Moseley A, Spremulli LL; J Biol Chem. 2001;276:19363-19374. PMID:11279123