Family

Ribosomal protein L2, bacterial/organellar-type (IPR005880)

Short name: Ribosomal_L2_bac/org-type

Family relationships

Description

Ribosomes are the particles that catalyse mRNA-directed protein synthesis in all organisms. The codons of the mRNA are exposed on the ribosome to allow tRNA binding. This leads to the incorporation of amino acids into the growing polypeptide chain in accordance with the genetic information. Incoming amino acid monomers enter the ribosomal A site in the form of aminoacyl-tRNAs complexed with elongation factor Tu (EF-Tu) and GTP. The growing polypeptide chain, situated in the P site as peptidyl-tRNA, is then transferred to aminoacyl-tRNA and the new peptidyl-tRNA, extended by one residue, is translocated to the P site with the aid the elongation factor G (EF-G) and GTP as the deacylated tRNA is released from the ribosome through one or more exit sites [PMID: 11297922, PMID: 11290319]. About 2/3 of the mass of the ribosome consists of RNA and 1/3 of protein. The proteins are named in accordance with the subunit of the ribosome which they belong to - the small (S1 to S31) and the large (L1 to L44). Usually they decorate the rRNA cores of the subunits.

Many ribosomal proteins, particularly those of the large subunit, are composed of a globular, surfaced-exposed domain with long finger-like projections that extend into the rRNA core to stabilise its structure. Most of the proteins interact with multiple RNA elements, often from different domains. In the large subunit, about 1/3 of the 23S rRNA nucleotides are at least in van der Waal's contact with protein, and L22 interacts with all six domains of the 23S rRNA. Proteins S4 and S7, which initiate assembly of the 16S rRNA, are located at junctions of five and four RNA helices, respectively. In this way proteins serve to organise and stabilise the rRNA tertiary structure. While the crucial activities of decoding and peptide transfer are RNA based, proteins play an active role in functions that may have evolved to streamline the process of protein synthesis. In addition to their function in the ribosome, many ribosomal proteins have some function 'outside' the ribosome [PMID: 11290319, PMID: 11114498].

The protein L2 is found in all ribosomes and is one of the best conserved proteins of this mega-dalton complex. L2 is elongated, exposing one end of the protein to the surface of the intersubunit interface of the 50 S subunit and is essential for the association of the ribosomal subunits and might participate in the binding and translocation of the tRNAs [PMID: 11114255]. This entry represents bacterial, chloroplast and mitochondrial forms.

GO terms

Biological Process

GO:0006412 translation

Molecular Function

GO:0003723 RNA binding
GO:0003735 structural constituent of ribosome
GO:0016740 transferase activity

Cellular Component

GO:0015934 large ribosomal subunit

Contributing signatures

Signatures from InterPro member databases are used to construct an entry.
HAMAP
TIGRFAMs