Site-directed spin labeling of 2′-amino groups in RNA with isoindoline nitroxides that are resistant to reduction

Post-print (lokagerð höfundar)Two aromatic isothiocyanates, derived from isoindoline nitroxides, were synthesized and selectively reacted with 2′-amino groups in RNA. The spin labels displayed limited mobility in RNA, making them promising candidates for distance measurements by pulsed EPR. After conjugation to RNA, a tetraethyl isoindoline derivative showed significant stability under reducing conditions.This work was supported by the Icelandic Research Fund (141062-051). S.S. and A.P.J. gratefully acknowledge doctoral fellowships provided by the University of Iceland. The authors thank Dr S. Jonsdottir for assistance with collecting analytical data for structural characterization of compounds prepared and members of the Sigurdsson research group for critical reading of the manuscript.Peer reviewe