Scaling Catalytic Contributions of Small Self‐Cleaving Ribozymes

Autor: Michaela Egger, Raphael Bereiter, Stefan Mair, Ronald Micura
Rok vydání: 2022
Předmět:
Zdroj: Angewandte Chemie. 134
ISSN: 1521-3757
0044-8249
DOI: 10.1002/ange.202207590
Popis: Nucleolytic ribozymes utilize general acid-base catalysis to perform phosphodiester cleavage. In most ribozyme classes, a conserved active site guanosine is positioned to act as general base, thereby activating the 2'-OH group to attack the scissile phosphate (γ-catalysis). Here, we present an atomic mutagenesis study for the pistol ribozyme class. Strikingly, "general base knockout" by replacement of the guanine N1 atom by carbon results in only 2.7-fold decreased rate. Therefore, the common view that γ-catalysis critically depends on the N1 moiety becomes challenged. For pistol ribozymes we found that γ-catalysis is subordinate in overall catalysis, made up by two other catalytic factors (α and δ). Our approach allows scaling of the different catalytic contributions (α, β, γ, δ) with unprecedented precision and paves the way for a thorough mechanistic understanding of nucleolytic ribozymes with active site guanines.
Databáze: OpenAIRE
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