Native Mass Spectrometric Insights into the Formation and Stability of DNA Triplexes

Deoxyribonucleic acid is a genetic biomacromolecule that contains the inherited information required to build and maintain a living organism. While the canonical duplex DNA structure is rigorously characterized, the structure and function of higher order DNA structures such as DNA triplexes are comparatively poorly understood. Previous literature has shown that these triplexes can form under physiological conditions, and native mass spectrometry offers a useful platform to study their formation and stability. However, experimental conditions including buffer salt concentration, pH, and instrumentation parameters such as ion mode can confound analysis by impacting the amount of triplex observed by mass spectrometry. Using model 30mer Y-type triplex sequences, we demonstrate the influence a range of experimental variables have on the detection of DNA triplex structures, informing suitable conditions for the study. When carefully considered conditions are used, mass spectrometry offers a powerful complementary tool for the analysis of higher order DNA assemblies.