Physiological role of RsgA in ribosome biosynthesis.

RsgA is a unique GTP hydrolytic protein, in which the GTPase activity is significantly enhanced by the small ribosomal subunit. Depletion of RsgA causes slow cell growth as well as defects in the subunit assembly of the ribosome and the 16S rRNA processing, suggesting its involvement in the maturation of the small subunit. Several antibiotics bound to the decoding center of the small subunit inhibited the ribosome-dependent GTPase activity of RsgA. Our recent study using chemical modification indicates that the binding of RsgA induces conformational changes around the A site, P site, and helix 44. These results suggest that RsgA is involved in the maturation step of the decoding center of the small subunit of ribosome. Here, we also show a physiological role of RsgA under stress condition.