August 13, 2008
Protein Synthesis Evolution is Challenged
A U.S. study of transfer RNA is challenging long-held theories concerning the evolutionary history of protein synthesis.
University of Illinois researchers report the dual functions of transfer RNA, or tRNA -- a molecule that delivers amino acids to the protein-building machinery of the cell -- apparently originated independently.
During protein synthesis, tRNA's dual function is reflected in its unique L-shaped structure, the scientists said. One end of the molecule decodes messenger RNA -- a molecule that carries instructions for the sequence of amino acids in a protein -- while the other transfers a specific amino acid to the growing protein chain.
Previously scientists assumed the two functional domains of tRNA had evolved together. But Caetano-Anolles and researcher Feng-Jie Sun determined the two functions have different evolutionary histories, which suggests they were acquired at different points in time.
The research appeared in the July 30 issue of the online journal PLoS One.