Large ribosomal subunit protein uL30-like, ferredoxin-like fold domain (Ribosomal_uL30_ferredoxin-like)
Type: Domain

Ribosomal protein uL30 is one of the proteins from the large ribosomal subunit. uL30 belongs to a family of ribosomal proteins which, on the basis of sequence similarities , groups bacteria and archaea uL30, yeast mitochondrial L33, and Drosophila melanogaster, Dictyostelium discoideum (Slime mold), fungal and mammalian L7 ribosomal proteins, also referred to as uL30m. uL30 from bacteria are small proteins of about 60 residues, those from archaea are proteins of about 150 residues, and eukaryotic L7 are proteins of about 250 to 270 residues. L30 is missing in some groups of bacteria, such as the CPR group, the PVC group, Cyanobacteria, and some symbionts, which suggests that it is non-essential .

This entry represents a domain with a ferredoxin-like fold, with a core structure consisting of core: β-α-β-α-β. This domain is found in prokaryotic ribosomal protein uL30 (short-chain member of the family), as well as in archaeal uL30 (L30a) (long-chain member of the family), the later containing an additional C-terminal (sub)domain. It is also found in nucleolar proteins with similarity to large ribosomal subunit L7 proteins. These are constituents of 66S pre-ribosomal particles and play an essential role in processing of precursors to the large ribosomal subunit RNAs .

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 . 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 .