The Structural Basis of Ribozyme- Catalyzed RNA Assembly

摘要

The discovery of RNA enzymes (or ribozymes) in the 1980s (1-3) reignited interest in the chemical basis of the origin of life and resulted in formulation of the RNA World hypothesis (4). If RNA, in principle, can be both a genome and a catalyst, prebiotic self-replicating RNA molecules are likely an immediate evolutionary precursor and possibly a constituent of the first living organisms. All extant protein-based RNA polymerases synthesize RNA by catalyzing the templated ligation of a nucleo-tide triphosphate to form a 5' to 3' phosphodiester bond (Fig. 1A). Although natural ribozymes catalyze various phosphodiester bond isomerizations, hydrolysis, and even peptide bond formation (5), no naturally occurring nucleotide triphosphate ligase ribozyme that catalyzes the reaction required of an RNA polymerase has been discovered.