One of the early assembly proteins, it binds 23S rRNA; is essential for growth. One of the proteins that surround the polypeptide exit tunnel on the outside of the subunit. Acts as the docking site for trigger factor (PubMed:12226666) for Ffh binding to the ribosome (SRP54, PubMed:12756233 and PubMed:12702815) and to nascent polypeptide chains (PubMed:12756233). Part of the 50S ribosomal subunit (PubMed:391594, PubMed:10094780, PubMed:12809609, PubMed:16272117, PubMed:21499241, PubMed:25310980, PubMed:24844575, PubMed:27934701, PubMed:27906160, PubMed:27906161). Contacts protein L29 and trigger factor. Might also contact SecE and probably does contact SecG and SecY when the SecYEG translocation complex is docked with the ribosome (PubMed:16292303). Belongs to the universal ribosomal protein uL23 family.