| Primary Identifier | IPR000911 | Type | Family |
| Short Name | Ribosomal_L11/L12 |
| description | 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 [], 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 [, , , ]. In E. coli, the C-terminal half of L11 has been shown []to be in an extended and loosely folded conformation and is likely to be buried within the ribosomal structure.Ribosomal protein L11, together with proteins L10 and L7/L12, and 23S rRNA, form the L7/L12 stalk on the surface of the large subunit of the ribosome. The homologous eukaryotic cytoplasmic protein is also called 60S ribosomal protein L12, which is distinct from the L12 involved in the formation of the L7/L12 stalk. The C-terminal domain (CTD) of L11 is essential for binding 23S rRNA, while the N-terminal domain (NTD) contains the binding site for the antibiotics thiostrepton and micrococcin. L11 and 23S rRNA form an essential part of the GTPase-associated region (GAR). Based on differences in the relative positions of the L11 NTD and CTD during the translational cycle, L11 is proposed to play a significant role in the binding of initiation factors, elongation factors, and release factors to the ribosome. Several factors, including the class I release factors RF1 and RF2, are known to interact directly with L11. In eukaryotes, L11 has been implicated in regulating the levels of ubiquinated p53 and MDM2 in the MDM2-p53 feedback loop, which is responsible for apoptosis in response to DNA damage. In bacteria, the "stringent response"to harsh conditions allows bacteria to survive, and ribosomes that lack L11 are deficient in stringent factor stimulation [, , , , , , , , , , , ]. |
