This superfamily includes a structural domain found in the ribosomal protein S6 from the small (30S) subunit of the ribosome, and in the translation elongation factor EF1B. This entry also includes homologues such as beta-AP (Alzheimer beta-peptide), PilO (a membrane protein involved in the assembly of pilin in T4P, type 4 pili INTERPRO:IPR007445), bacterial, red algal chloroplast and cyanelle S6 ribosomal proteins. Structurally it is an alpha+beta sandwich domain (four-stranded antiparallel beta-sheets flanked by two alpha-helices) and exhibits a Ferredoxin-like fold.

Folding of the ribosomal protein S6 is a malleable process controlled by two competing, and partly overlapping, folding nuclei. The structure of S6 is composed of two cooperative subunits or 'foldons', sigma1 and sigma2, that also act as competing nuclei in the folding process. PMID:22117065. In E. coli, ribosomal protein S6 is known to bind 16S rRNA, together with S18.

Elongation factor eEF1B alpha (also known as EF1B, EF-Ts or EF-1beta/gamma/delta) is a nucleotide exchange factor that is required to regenerate EF1A from its inactive form (EF1A-GDP) to its active form (EF1A-GTP). EF1A is then ready to interact with a new aminoacyl-tRNA to begin the cycle again. EF1B is more complex in eukaryotes than in bacteria, and can consist of three subunits: EF1B-alpha (or EF-1beta), EF1B-gamma (or EF-1gamma) and EF1B-beta (or EF-1delta).

In P. aeruginosa, PilM/N/O/P proteins are essential for T4P biogenesis, the periplasmic domains of PilN and PilO interact to form a heterodimer. PilO was shown to play a key role in the proper folding of PilN.

PFAM:PF01250, INTERPRO:IPR014717, INTERPRO:IPR035980,PMID:11106763,PMID:10944185,PMID:22117065,PMID:12762045