S4 protein domain

S4
Identifiers
Symbol	S4
Pfam	PF01479
Pfam clan	CL0492
InterPro	IPR002942
PROSITE	PDOC00549
SCOP2	1c06 / SCOPe / SUPFAM
CDD	cd00165
Available protein structures: Pfam   structures / ECOD   PDB RCSB PDB; PDBe; PDBj PDBsum structure summary

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. Aravind L, Koonin EV (March 1999). "Novel predicted RNA-binding domains associated with the translation machinery". J. Mol. Evol. 48 (3): 291–302. doi:10.1007/pl00006472. PMID   10093218. S2CID   8083860.
2. Maguire BA, Zimmermann RA (March 2001). "The ribosome in focus". Cell. 104 (6): 813–6. doi: 10.1016/s0092-8674(01)00278-1 . PMID   11290319. S2CID   8174178.
3. Chandra Sanyal S, Liljas A (December 2000). "The end of the beginning: structural studies of ribosomal proteins". Curr. Opin. Struct. Biol. 10 (6): 633–6. doi:10.1016/S0959-440X(00)00143-3. PMID   11114498.
4. Davies C, Gerstner RB, Draper DE, Ramakrishnan V, White SW (1998). "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. doi:10.1093/emboj/17.16.4545. PMC   1170785 . PMID   9707415.

This article incorporates text from the public domain Pfam and InterPro: IPR002942