SSU ribosomal protein S10p (S20e); Involved in the binding of tRNA to the ribosomes. Belongs to the universal ribosomal protein uS10 family.

SSU ribosomal protein S2p (SAe); Belongs to the universal ribosomal protein uS2 family.

SSU ribosomal protein S7p (S5e); One of the primary rRNA binding proteins, it binds directly to 16S rRNA where it nucleates assembly of the head domain of the 30S subunit. Is located at the subunit interface close to the decoding center, probably blocks exit of the E-site tRNA; Belongs to the universal ribosomal protein uS7 family.

SSU ribosomal protein S5p (S2e); Located at the back of the 30S subunit body where it stabilizes the conformation of the head with respect to the body. Belongs to the universal ribosomal protein uS5 family.

SSU ribosomal protein S11p (S14e); Located on the platform of the 30S subunit, it bridges several disparate RNA helices of the 16S rRNA. Forms part of the Shine- Dalgarno cleft in the 70S ribosome; Belongs to the universal ribosomal protein uS11 family.

RNA 3'-terminal phosphate cyclase; Catalyzes the conversion of 3'-phosphate to a 2',3'-cyclic phosphodiester at the end of RNA. The mechanism of action of the enzyme occurs in 3 steps: (A) adenylation of the enzyme by ATP; (B) transfer of adenylate to an RNA-N3'P to produce RNA-N3'PP5'A; (C) and attack of the adjacent 2'-hydroxyl on the 3'-phosphorus in the diester linkage to produce the cyclic end product. The biological role of this enzyme is unknown but it is likely to function in some aspects of cellular RNA processing.

SSU ribosomal protein S15p (S13e); Forms an intersubunit bridge (bridge B4) with the 23S rRNA of the 50S subunit in the ribosome.

SSU ribosomal protein S12p (S23e); Interacts with and stabilizes bases of the 16S rRNA that are involved in tRNA selection in the A site and with the mRNA backbone. Located at the interface of the 30S and 50S subunits, it traverses the body of the 30S subunit contacting proteins on the other side and probably holding the rRNA structure together. The combined cluster of proteins S8, S12 and S17 appears to hold together the shoulder and platform of the 30S subunit.

SSU ribosomal protein S13p (S18e); Located at the top of the head of the 30S subunit, it contacts several helices of the 16S rRNA. In the 70S ribosome it contacts the 23S rRNA (bridge B1a) and protein L5 of the 50S subunit (bridge B1b), connecting the 2 subunits; these bridges are implicated in subunit movement. Contacts the tRNAs in the A and P-sites. Belongs to the universal ribosomal protein uS13 family.