<p>Ribosomal protein S2 is is a protein of 235 to 394 amino-acid residues and is one of the proteins from the small ribosomal subunit. S2 belongs to a family of ribosomal proteins which, on the basis of sequence similarities [<cite idref="PUB00044781"/>, <cite idref="PUB00001672"/>], groups: </p><ul><li>Eubacterial S2. </li><li>Algal and plant chloroplast S2. </li><li>Cyanelle S2. </li><li>Archaebacterial S2. </li><li>Higher eukaryotes P40 (previously thought to be a laminin receptor). </li> <li>Yeast NAB1. </li><li>Plant mitochondrial S2. </li><li>Yeast mitochondrial MRP4. </li></ul>