Practice question

Ribosome qualifies as ribozyme because essential catalytic activity peptide bond formation is mediated by ribosomal RNA not protein. Structural analyses reveal active site composed of conserved nucleotides in domain V of 23S rRNA forming induced-fit pocket that orients substrates, stabilizes tetrahedral intermediate via hydrogen bonding and contributes 2' OH of P-site tRNA as substrate-assisted catalyst. Removal of nearly all ribosomal proteins retains peptidyl transferase activity, whereas mutations in 23S rRNA abolish function, proving RNA catalysis, supporting RNA world hypothesis for primordial translation.