Albany 2013: Book of Abstracts
June 11-15 2013
©Adenine Press (2012)
Origins and Evolution of the Translation Machinery
The protein synthesis machinery largely evolved prior to the last common ancestor and hence its study can provide insight to early events in the origin of life, including the transition from the hypothetical RNA World to living systems as we know them. By utilizing information from, primary sequences, atomic resolution structures, and functional properties of the various components, it is possible to identify timing relationships (Hsiao et al., 2009; Fox, 2010). Taken together, these timing events are used to develop a preliminary time line for major evolutionary events leading to the modern protein synthesis machinery. It has been argued that a key initial event was the hybridization of two or more RNAs that created the peptidyl transferase center, (PTC), of the ribosome (Agmon et al. 2005). The PTC, left side of figure, contains a characteristic cavity/pore that serves as the entrance to the exit tunnel and is thought to be essential to the catalysis (Fox et al., 2012). This cavity is distinct from typical RNA pores (right side of figure) in that the nitrogenous bases face towards the lumen of the pore and thus are available for hydrogen bonding interactions. In typical RNA pores, the bases carefully avoid the lumen region. In support of Agmon et al.2005), it is argued that this key difference reflects the fact the pore was created by an early hybridization event rather than normal RNA folding.
This work was supported by the NASA Center for Ribosome Evolution and Adaptation at the Georgia Institute of Technology (NNA09DA78A), A NASA Earth and Space Science Fellowship (10-Planet10R-0025) to QT and a NASA Planetary Biology Internship award to MR.
Fox, G.E. (2010). Origin and evolution of the ribosome. Cold Spring Harb. Perspect. Biol., 2, a003483.
Hsiao C., Mohan, S., Kalahar, B.K., & Williams, L.D. Peeling the onion: ribosomes are ancient molecular fossils. (2009). Mol. Biol. Evol. 26, 2415-2425
George E. Fox
Department Biology & Biochemistry