PTHR11205

RIBOSOMAL PROTEIN S7

PANTHER entry
Member databasePANTHER
PANTHER typefamily

Description
Imported from IPR000235

This entry includes the small ribosomal subunit protein uS7, formerly referred to as 30S ribosomal proteins S7 (bacterial, archaeal, plastid, mitochondrial), and eukaryotic 40S ribosomal proteins S5 (cytoplasmic)
[0, 0, 2, 1]
. 30S ribosomal protein S7 contacts ribosomal proteins S9 and S11. It is also one of the primary rRNA binding proteins - it binds directly to 16S rRNA - where it nucleates assembly of the head domain of the 30S subunit
[3]
. S7 is located at the subunit interface close to the decoding centre, where it has been shown to contact mRNA. It has also been shown to contact tRNA in both the P and E sites; it probably blocks exit of the E site tRNA.

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
[6, 5]
. 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
[5, 4]
.

References
Imported from IPR000235

1.Nucleolar maturation of the human small subunit processome. Singh S, Vanden Broeck A, Miller L, Chaker-Margot M, Klinge S. Science 373, eabj5338, (2021). PMID: 34516797

2.Structures of the human and Drosophila 80S ribosome. Anger AM, Armache JP, Berninghausen O, Habeck M, Subklewe M, Wilson DN, Beckmann R. Nature 497, 80-5, (2013). PMID: 23636399

3.Ribosomal protein S7 from Escherichia coli uses the same determinants to bind 16S ribosomal RNA and its messenger RNA. Robert F, Brakier-Gingras L. Nucleic Acids Res. 29, 677-82, (2001). View articlePMID: 11160889

4.The end of the beginning: structural studies of ribosomal proteins. Chandra Sanyal S, Liljas A. Curr. Opin. Struct. Biol. 10, 633-6, (2000). View articlePMID: 11114498

5.The ribosome in focus. Maguire BA, Zimmermann RA. Cell 104, 813-6, (2001). View articlePMID: 11290319

6.Atomic structures at last: the ribosome in 2000. Ramakrishnan V, Moore PB. Curr. Opin. Struct. Biol. 11, 144-54, (2001). View articlePMID: 11297922

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