InterPro domain: IPR036769

Ribosomal protein L11 is one of the proteins from the large ribosomal subunit. In Escherichia coli, L11 is known to bind directly to the 23S rRNA and plays a significant role during initiation, elongation, and termination of protein synthesis. It belongs to a family of ribosomal proteins which, on the basis of sequence similarities [ 1 ], groups bacteria, plant chloroplast, red algal chloroplast, cyanelle and archaeabacterial L11; and mammalian, plant and yeast L12 (YL15). L11 is a protein of 140 to 165 amino-acid residues. L11 consists of a 23S rRNA binding C-terminal domain and an N-terminal domain that directly contacts protein synthesis factors. These two domains are joined by a flexible linker that allows inter-domain movement during protein synthesis. While the C-terminal domain of L11 binds RNA tightly, the N-terminal domain makes only limited contacts with RNA and is proposed to function as a switch that reversibly associates with an adjacent region of RNA [ 2 , 3 , 4 , 5 ]. In E. coli, the C-terminal half of L11 has been shown [ 6 ] to be in an extended and loosely folded conformation and is likely to be buried within the ribosomal structure.

This entry represents the C-terminal domain of L11/L12. The domain consists of a three-helical bundle and a short parallel two-stranded beta-ribbon, with an overall alpha3-beta4-alpha4-alpha5-beta5 topology. All five secondary structure elements contribute to a conserved hydrophobic core. The domain is characterised by two extended loops that are disordered in the absence of the RNA but have defined structures in the complex [ 7 ].

1. The 26S rRNA binding ribosomal protein equivalent to bacterial protein L11 is encoded by unspliced duplicated genes in Saccharomyces cerevisiae. Nucleic Acids Res. 18, 4409-16
2. Translational regulation via L11: molecular switches on the ribosome turned on and off by thiostrepton and micrococcin. Mol. Cell 30, 26-38
3. A detailed view of a ribosomal active site: the structure of the L11-RNA complex. Cell 97, 491-502
4. Recognition of ribosomal protein L11 by the protein trimethyltransferase PrmA. EMBO J. 26, 567-77
5. Multiple-site trimethylation of ribosomal protein L11 by the PrmA methyltransferase. Structure 16, 1059-66
6. Structural properties of ribosomal protein L11 from Escherichia coli. Biochem. Int. 19, 1323-38