With S4 and S12 plays an important role in translational accuracy. Part of the 30S ribosomal subunit. Contacts protein S4. The N-terminal domain interacts with the head of the 30S subunit; the C-terminal domain interacts with the body and contacts protein S4. The interaction surface between S4 and S5 is involved in control of translational fidelity. Belongs to the universal ribosomal protein uS5 family.