InterPro domain: IPR003029

The S1 domain was originally identified in ribosomal protein S1 but is found in a large number of proteins involved in RNA metabolism. It belongs to the OB-fold family. The structure of the S1 RNA-binding domain from the Escherichia coli polynucleotide phosphorylase has been determined using NMR methods and consists of a five-stranded antiparallel beta barrel. Conserved residues on one face of the barrel and adjacent loops form the putative RNA-binding site [ 1 , 2 ].

The structure of the S1 domain is very similar to that of cold shock proteins. This suggests that they may both be derived from an ancient nucleic acid-binding protein [ 3 ].

This entry does not include translation initiation factor IF-1 S1 domains.

1. The solution structure of the S1 RNA binding domain: a member of an ancient nucleic acid-binding fold. Cell 88, 235-42
2. Structural basis for targeting the ribosomal protein S1 of Mycobacterium tuberculosis by pyrazinamide. Mol. Microbiol. 95, 791-803