Binds directly to 23S rRNA. The L1 stalk is quite mobile in the ribosome, and is involved in E site tRNA release. Protein L1 is also a translational repressor protein, it controls the translation of the L11 operon by binding to its mRNA. Peptides originating from the N-terminal end of L1 have antibacterial activity against bacteria such as E.coli and B.megaterium and modest antifungal activities. Has no effect on H.pylori itself. Peptides are not hemolytic against mammalian cells. These peptides may be released in the stomach during altruistic lysis to kill other fast growing bacteria. Part of the 50S ribosomal subunit. The antimicrobial peptide HP (2-20) forms a short alpha-helix. Increasing the amphiphilicity of the helix increases its antimicrobial activities. Belongs to the universal ribosomal protein uL1 family.