1986/01/31 by Arthur J. Zaug, Thomas R. Cech · 5 citations
Biochemistry, Genetics and Molecular Biology · Environmental Science · #Bacteriophages and microbial interactions #RNA and protein synthesis mechanisms #RNA modifications and cancer
paper · doi:10.1126/science.3941911
openalex publication_date 1986/01/31 · openalex created_date 2016/06/24 · openalex updated_date 2026/08/03
A shortened form of the self-splicing ribosomal RNA (rRNA) intervening sequence of Tetrahymena thermophila acts as an enzyme in vitro. The enzyme catalyzes the cleavage and rejoining of oligonucleotide substrates in a sequence-dependent manner with Km = 42 microM and kcat = 2 min-1. The reaction mechanism resembles that of rRNA precursor self-splicing. With pentacytidylic acid as the substrate, successive cleavage and rejoining reactions lead to the synthesis of polycytidylic acid. Thus, the RNA molecule can act as an RNA polymerase, differing from the protein enzyme in that it uses an internal rather than an external template. At pH 9, the same RNA enzyme has activity as a sequence-specific ribonuclease.