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

Abstract

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.