Biology:S4 protein domain

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S4
PDB 2qoy EBI.png
Identifiers
SymbolS4
PfamPF01479
Pfam clanCL0492
InterProIPR002942
PROSITEPDOC00549
SCOP21c06 / SCOPe / SUPFAM
CDDcd00165

In molecular biology, S4 domain refers to a small RNA-binding protein domain found in a ribosomal protein named uS4 (called S9 in eukaryotes). The S4 domain is approximately 60-65 amino acid residues long, occurs in a single copy at various positions in different proteins and was originally found in pseudouridine syntheses, a bacterial ribosome-associated protein.[1]

The S4 protein helps to initiate assembly of the 16S rRNA. In this way proteins serve to organise and stabilise the rRNA tertiary structure.[2][3]

Function

The function of the S4 domain is to be an RNA-binding protein. S4 is a multifunctional protein, and it must bind to the 16S ribosomal RNA. In addition, the S4 domain binds a complex pseudoknot and represses translation. More specifically, this protein domain delivers nucleotide-modifying enzymes to RNA and to regulates translation through structure specific RNA binding.[1]

Structure

The S4 protein domain is composed of three alpha helices and five beta strands. It is organized as an antiparallel sheet in a Greek key motif.[4]

References

  1. 1.0 1.1 "Novel predicted RNA-binding domains associated with the translation machinery". J. Mol. Evol. 48 (3): 291–302. March 1999. doi:10.1007/pl00006472. PMID 10093218. https://zenodo.org/record/1232574. 
  2. "The ribosome in focus". Cell 104 (6): 813–6. March 2001. doi:10.1016/s0092-8674(01)00278-1. PMID 11290319. 
  3. "The end of the beginning: structural studies of ribosomal proteins". Curr. Opin. Struct. Biol. 10 (6): 633–6. December 2000. doi:10.1016/S0959-440X(00)00143-3. PMID 11114498. 
  4. "The crystal structure of ribosomal protein S4 reveals a two-domain molecule with an extensive RNA-binding surface: one domain shows structural homology to the ETS DNA-binding motif.". EMBO J 17 (16): 4545–58. 1998. doi:10.1093/emboj/17.16.4545. PMID 9707415. 
This article incorporates text from the public domain Pfam and InterPro: IPR002942