A Versatile Approach to Attachment of Triarylmethyl Labels to DNA for Nanoscale Structural EPR Studies at Physiological Temperatures

作者：Shevelev Georgiy Yu.; Gulyak Evgeny L.; Lomzov Alexander A.; Kuzhelev Andrey A.; Krumkacheva Olesya A.; Kupryushkin Maxim S.; Tormyshev Victor M.; Fedin Matvey V.; Bagryanskaya Elena G.^*; Pyshnyi Dmitrii V.^*

来源：Journal of Physical Chemistry B, 2018, 122(1): 137-143.

DOI：10.1021/acs.jpcb.7b10689

Triarylmethyl (trityl, TAM) radicals are a promising class of spin labels for nanometer-scale distance measurements in biomolecules at physiological temperatures. However, to date, existing approaches to site-directed TAM labeling of DNA have been limited to label attachment at the termini of oligonucleotides, thus hindering a majority of demanded applications. Herein, we report a new versatile strategy for TAM attachment at arbitrary sites of nucleic acids. It utilizes an achiral non-nucleoside phosphoramidite monomer for automated solid-phase synthesis of oligonucleotides, which are then postsynthetically functionalized with TAM. We demonstrate a synthesis of a set of oligonucleotide complexes that are TAM-labeled at internal or terminal sites, as well as the possibility of measuring interspin distances up to similar to 5-6 nm at 298 K using double quantum coherence electron paramagnetic resonance (EPR). Implementation of the developed approach strongly broadens the scope of nucleic acids and nucleoprotein complexes available for nanoscale structural EPR studies at room temperatures.

• 出版日期2018-1-11