This protein binds specifically to 23S rRNA; its binding is stimulated by other ribosomal proteins, e.g. L4, L17, and L20. It is important during the early stages of 50S assembly. It makes multiple contacts with different domains of the 23S rRNA in the assembled 50S subunit and ribosome (By similarity). The globular domain of the protein is one of the proteins that surrounds the polypeptide exit tunnel on the outside of the subunit, while an extended beta-hairpin is found that penetrates into the center of the 70S ribosome. This extension seems to form part of the wall of the exit tunnel (By similarity). Deleting residues 82 to 84 (the equivalent deletion in E.coli renders cells resistant to erythromycin) would probably cause the tip of the hairpin to penetrate into the tunnel. Part of the 50S ribosomal subunit. Belongs to the universal ribosomal protein uL22 family.