リボソームにおけるペプチド生成機構の起源

概要

論文の詳細を見る
Peptide bond formation catalyzed on the ribosome is a crucial event in the life on earth. The ribosome is a supercomplex of ribonucleoprotein particles containing both RNAs and proteins, and the peptide bond is produced on the peptidyl transferase center (PTC) of the large subunit of the ribosome. The high-resolution structures of the ribosome showed that the PTC is composed of only RNA. Although the ribosome seems to be a ribozyme, the foundation of the PTC and the evolutionary route of the ribosome are not clear. In this study, a possible evolutionary pathway for ribosome formation has been presented by combining a model experiment and the structural analysis of the ribosome. The current ribosome-catalyzed reaction could have evolved from a primitive system in the RNA world comprising proto-tRNA molecules like the minihelix. The missing link in the evolutionary route of the modern ribosome can be solved by considering tRNAs as primordial molecules comprising proto-ribosomes and proto-tRNAs, which form a symmetrical RNA dimer to constitute the PTC.
2012-06-20