Protonation-Dependent Base Flipping at Neutral pH in the Catalytic Triad of a Self-Splicing Bacterial Group II Intron

Pechlaner, Maria; Donghi, Daniela; Zelenay, Veronika; Sigel, Roland K O

doi:10.1002/anie.201504014

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Pechlaner, M., Donghi, D., Zelenay, V., & Sigel, R. K. O. (2015). Protonation-Dependent Base Flipping at Neutral pH in the Catalytic Triad of a Self-Splicing Bacterial Group II Intron. Angewandte Chemie Internationale Edition, 54(33), 9687–9690. https://doi.org/10.1002/anie.201504014

Abstract

NMR spectroscopy has revealed pH-dependent structural changes in the highly conserved catalytic domain 5 of a bacterial group II intron. Two adenines with pKa values close to neutral pH were identified in the catalytic triad and the bulge. Protonation of the adenine opposite to the catalytic triad is stabilized within a G(syn)–AH+(anti) base pair. The pH-dependent anti-to-syn flipping of this G in the catalytic triad modulates the known interaction with the linker region between domains 2 and 3 (J23) and simultaneously the binding of