One of the primary rRNA binding proteins, it binds directly near the 3'-end of the 23S rRNA, where it nucleates assembly of the 50S subunit (By similarity). Strongly stimulates 23S rRNA precursor processing by mini-ribonuclease 3 (MrnC); 20-30% DMSO can replace L3, suggesting the protein may alter rRNA conformation. Part of the 50S ribosomal subunit (PubMed:30126986). Forms a cluster with proteins L14 and L19 (By similarity). Interacts with RNA helicase CshA (PubMed:23175651). Belongs to the universal ribosomal protein uL3 family.