The structural domains that comprise this superfamily share the structure of the ribosomal protein S19, a single domain of the 40S small subunit of the eukaryotic ribosome. This superfamily entry includes a number of eukaryotic and archaebacterial ribosomal proteins, such as mammalian S19, Drosophila S19, Ascaris lumbricoides S19g (ALEP-1) and S19s, yeast YS16 (RP55A and RP55B), Aspergillus S16 and Haloarcula marismortui HS12. This protein is esse3a1pntial for yeast viability and for early stages of development in mice. Since there is no homologue of RPS19 in bacteria, for which high-resolution structures of the small ribosomal subunit are available, the structure of RPS19 and its precise location within the 40S subunit remain unknown.

Disruption as well as point mutations of the rps19 gene in yeast and human cells affect maturation of the pre-ribosomal RNA (pre-rRNA) and block production of the 40S ribosomal subunits. Specifically, mutations in the rps19 gene are associated with the rare congenital disease Diamond-Blackfan anaemia (DBA). S19 forms a five-helix bundle organised around a central amphipathic alpha-helix, which corresponds to the DBA mutation hot spot.

PFAM:PF01090, INTERPRO:IPR001266, INTERPRO:IPR038111,PMID:17726054