Binds directly to 23S rRNA. The L1 stalk is quite mobile in the ribosome, and is involved in E site tRNA release (By similarity). Protein L1 is also a translational repressor protein, it controls the translation of the L11 operon by binding to its mRNA. Part of the 50S ribosomal subunit. Belongs to the universal ribosomal protein uL1 family.