This superfamily entry represents the ribosomal protein S10 found in the small subunit (50S) of the bacterial ribosome. The superfamily also includes S10 homologues found in other organisms, such as algal chloroplast S10, cyanelle S10, archaebacterial S10, Marchantia polymorpha and Prototheca wickerhamii mitochondrial S10, Arabidopsis thaliana mitochondrial S10 (nuclear encoded), vertebrate S20, plant S20 and yeast URP2. Structurally, this ribosomal protein is a whole chain domain and has a ferrodoxin-like fold, which consists of an alpha+beta sandwich with antiparallel beta-sheet.

The small ribosomal subunit protein S10 consists of about 100 amino acid residues. In Escherichia coli, S10 is involved in binding tRNA to the ribosome, and also operates as a transcriptional elongation factor.

In phages, S10 participates together with NusB protein (N-utilisation substance B) in processive transcription antitermination. NusE is identical to r-protein S10. In the transcriptionally active NusB-S10 complex, S10 adopts the same fold as in the 30S subunit and is blocked from simultaneous association with the ribosome. The molecular mechanisms by which S10 can act as a translation or a transcription factor are not understood yet.

PFAM:PF00338, INTERPRO:IPR036838,PMID:25271403