RNA-binding domain, S1, IF1 type (IPR006196)

Short name: RNA-binding_domain_S1_IF1

Overlapping homologous superfamilies

Domain relationships


The S1 domain of around 70 amino acids, originally identified in ribosomal protein S1, is found in a large number of RNA-associated proteins. It has been shown that S1 proteins bind RNA through their S1 domains with some degree of sequence specificity. This type of S1 domain is found in translation initiation factor 1.

The solution structure of one S1 RNA-binding domain from Escherichia coli polynucleotide phosphorylase has been determined [PMID: 9008164]. It displays some similarity with the cold shock domain (CSD) (IPR002059). Both the S1 and the CSD domain consist of an antiparallel beta barrel of the same topology with 5 beta strands. This fold is also shared by many other proteins of unrelated function and is known as the OB fold. However, the S1 and CSD fold can be distinguished from the other OB folds by the presence of a short 3(10) helix at the end of strand 3. This unique feature is likely to form a part of the DNA/RNA-binding site.

This entry is specific for bacterial, chloroplastic and eukaryotic IF-1 type S1 domains.

GO terms

Biological Process

GO:0006413 translational initiation

Molecular Function

GO:0003723 RNA binding
GO:0003743 translation initiation factor activity

Cellular Component

No terms assigned in this category.

Contributing signatures

Signatures from InterPro member databases are used to construct an entry.
PROSITE profiles