1-Deazainosine-impact on RNA structure and role in exploring ribozyme catalysis
Abstract
Synthetic RNAs bearing deazapurine nucleobases are powerful probes for dissecting RNA-catalyzed reactions by atomic mutagenesis. Here we systematically characterize RNA containing 1-deazainosine (c1I) and compare it with inosine (I). We first report the synthesis of a suitably protected c1I phosphoramidite and its incorporation into RNA by solid-phase synthesis. We then provide a comprehensive thermodynamic analysis of base-pair stability from UV-melting experiments, showing that c1I–C pairs are less stable than the corresponding I–C pairs. Although a two-hydrogen-bond Hoogsteen interaction between c1I and protonated C is conceivable, NMR spectroscopy indicates that c1I–C predominantly adopts a Watson–Crick-like geometry with a single hydrogen bond. These pairs are accommodated within RNA duplexes without disrupting neighboring base pairing. We also use c1I to probe poly(I:C) motifs that mimic viral double-stranded RNA, assessing how strand length governs duplex versus hairpin formation. Finally, atomic mutagenesis of the twister ribozyme with c1I supports the hypothesis that an active-site guanine participates directly in phosphodiester-bond cleavage. Together, these results clarify how deazapurines modulate nucleic-acid properties and provide guidance for their use in atomic mutagenesis to interrogate RNA catalysis.
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BibTeX
@article{mitteregger20261deazainosineimpact,
title = {{1-Deazainosine-impact on RNA structure and role in exploring ribozyme catalysis}},
author = {Christoph Mitteregger and Raphael Bereiter and Antoine Schramm and Eric Ennifar and Christoph Kreutz and Ronald Micura},
journal = {Chemical Science},
year = {2026},
month = jun,
doi = {10.1039/d6sc04009h},
url = {https://hal.science/hal-05772532v1},
note = {CC BY 4.0},
}
RIS
TY - JOUR
TI - 1-Deazainosine-impact on RNA structure and role in exploring ribozyme catalysis
AU - Christoph Mitteregger
AU - Raphael Bereiter
AU - Antoine Schramm
AU - Eric Ennifar
AU - Christoph Kreutz
AU - Ronald Micura
PY - 2026
DA - 2026/06/08
JO - Chemical Science
DO - 10.1039/d6sc04009h
UR - https://hal.science/hal-05772532v1
AB - Synthetic RNAs bearing deazapurine nucleobases are powerful probes for dissecting RNA-catalyzed reactions by atomic mutagenesis. Here we systematically characterize RNA containing 1-deazainosine (c1I) and compare it with inosine (I). We first report the synthesis of a suitably protected c1I phosphoramidite and its incorporation into RNA by solid-phase synthesis. We then provide a comprehensive thermodynamic analysis of base-pair stability from UV-melting experiments, showing that c1I–C pairs are less stable than the corresponding I–C pairs. Although a two-hydrogen-bond Hoogsteen interaction between c1I and protonated C is conceivable, NMR spectroscopy indicates that c1I–C predominantly adopts a Watson–Crick-like geometry with a single hydrogen bond. These pairs are accommodated within RNA duplexes without disrupting neighboring base pairing. We also use c1I to probe poly(I:C) motifs that mimic viral double-stranded RNA, assessing how strand length governs duplex versus hairpin formation. Finally, atomic mutagenesis of the twister ribozyme with c1I supports the hypothesis that an active-site guanine participates directly in phosphodiester-bond cleavage. Together, these results clarify how deazapurines modulate nucleic-acid properties and provide guidance for their use in atomic mutagenesis to interrogate RNA catalysis.
SN - 2041-6520
SN - 2041-6539
ER -