The Novel Chemical Mechanism of the Twister Ribozyme

Timothy J. Wilson, Yijin Liu, Christof Domnick, Stephanie Kath-Schorr, David M J Lilley (Lead / Corresponding author)

    Research output: Contribution to journalArticlepeer-review

    62 Citations (Scopus)

    Abstract

    We describe the multifactorial origins of catalysis by the twister ribozyme. We provide evidence that the adenine immediately 3′ to the scissile phosphate (A1) acts as a general acid. Substitution of ring nitrogen atoms indicates that very unusually the N3 of A1 is the proton donor to the oxyanion leaving group. A1 is accommodated in a specific binding pocket that raises its pKa toward neutrality, juxtaposes its N3 with the O5′ to be protonated, and helps create the in-line trajectory required for nucleophilic attack. A1 performs general acid catalysis while G33 acts as a general base. A 100-fold stereospecific phosphorothioate effect at the scissile phosphate is consistent with a significant stabilization of the transition state by the ribozyme, and functional group substitution at G33 indicates that its exocyclic N2 interacts directly with the scissile phosphate. A model of the ribozyme active site is proposed that accommodates these catalytic strategies.

    Original languageEnglish
    Pages (from-to)6151-6162
    Number of pages12
    JournalJournal of the American Chemical Society
    Volume138
    Issue number19
    Early online date6 May 2016
    DOIs
    Publication statusPublished - 18 May 2016

    ASJC Scopus subject areas

    • General Chemistry
    • Catalysis
    • Biochemistry
    • Colloid and Surface Chemistry

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