Incorporation of 5S RNA into 16S-23S RNA complex

5S RNA as such is not incorporated into 16S-23S RNA complex formed under reconstitution condition. However, the addition of 50S ribosomal proteins, L5, L18 and L25/L15 results in its incorporation in stoichiometric amount. None of the proteins added individually is capable of incorporating 5S RNA into the complex. Of the different combinations in pairs that are possible out of the four proteins, the pairs L5, L18 and L15, L18 stimulate the incorporation to some extent. Of the four possible triplets, L5, L18, L25 or L5, L15, L18 is the most efficient for maximum incorporation of 5S RNA. The presence of all the four proteins is no more effective than the combinations of the three.