The S1 domain is a

protein domain In molecular biology, a protein domain is a region of a protein's polypeptide chain that is self-stabilizing and that folds independently from the rest. Each domain forms a compact folded three-dimensional structure. Many proteins consist o ...

that was originally identified in ribosomal protein S1 but is found in a large number of RNA-associated proteins. The structure of the S1 RNA-binding domain from the ''

Escherichia coli ''Escherichia coli'' (),Wells, J. C. (2000) Longman Pronunciation Dictionary. Harlow ngland Pearson Education Ltd. also known as ''E. coli'' (), is a Gram-negative, facultative anaerobic, rod-shaped, coliform bacterium of the genus '' Esc ...

'' polynucleotide phosphorylase has been determined using

NMR Nuclear magnetic resonance (NMR) is a physical phenomenon in which nuclei in a strong constant magnetic field are perturbed by a weak oscillating magnetic field (in the near field) and respond by producing an electromagnetic signal with a ...

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. 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.

Function

The S1 domain is an essential in protein

translation Translation is the communication of the Meaning (linguistic), meaning of a #Source and target languages, source-language text by means of an Dynamic and formal equivalence, equivalent #Source and target languages, target-language text. The ...

as it interacts with the ribosome and messenger RNA. S1 bind to

RNA Ribonucleic acid (RNA) is a polymeric molecule essential in various biological roles in coding, decoding, regulation and expression of genes. RNA and deoxyribonucleic acid ( DNA) are nucleic acids. Along with lipids, proteins, and carbohydra ...

in a sequence specific manner.

Structure

This protein domain contains six motifs and 70 amino acids and it folds into a five-stranded antiparallel

beta barrel In protein structures, a beta barrel is a beta sheet composed of tandem repeats that twists and coils to form a closed toroidal structure in which the first strand is bonded to the last strand (hydrogen bond). Beta-strands in many beta-barrels are ...

. The structure of the S1 domain is very similar to that of

cold shock Cold shock response is a series of neurogenic cardio-respiratory responses caused by sudden immersion in cold water. In cold water immersions, such as by falling through thin ice, cold shock response is perhaps the most common cause of death. Als ...

proteins. This suggests that they may both be derived from an ancient nucleic acid-binding protein. Conserved residues on one face of the barrel and adjacent loops form the putative RNA-binding site.

References

{{InterPro content, IPR003029 Protein domains