This superfamily comprises the ribosomal protein S17 found in the small (40S) subunit of the eukaryotic and archaeabacterial ribosome. This entry also includes S17 (RPS17e) homologues from a variety of species, such as vertebrate, Drosophila and Neurospora crassa (crp-3) S17 as well as yeast S17a (RP51A) and S17b (RP51B). Mammalian S17E is a phosphoprotein component of eukaryotic ribosomes. Archaeal S17E proteins are about half the length of the eukaryotic homologues, which have an additional C-terminal region.

Structurally, S17 exhibits a DNA/RNA-binding 3-helical bundle fold, which consists of three helices with a close or partly open bundle and right-handed twist going up-and down. The three-helix bundle strikingly similar to the FF domain of human HYPA/FBP11, a novel phosphopeptide-binding fold. S17E bears a conserved positively charged surface acting as a robust scaffold for molecular recognition.

Mutations of the gene encoding ribosomal protein S17 were implicated in Diamond-Blackfan anemia (DBA). S17 is the target of the p70 S6 kinase, however the role that phosphorylation is currently unknown. Phosphorylation of human S17E has been shown to be inhibited by the immunosuppressant rapamycin. Ser and Thr residues that may serve as the site of phosphorylation.

PFAM:PF00833, INTERPRO:IPR036401,PMID:18218711