Quantitative characterization of oligomeric state of G-quadruplex antithrombin aptamers by size exclusion HPLC

A quantitative technique for estimation of the oligomeric state of G-quadruplexes has been developed for the first time. The simplest 15-mer G-quadruplex antithrombin aptamer HD1 and its analogues, namely RA36 as a covalent dimer of HD1 as well as GL2–HD1 as a non-covalent dimer with G-quadruplex lock, were used as model objects. HD1 and RA36 have been shown to be single-stranded G-quadruplexes, whereas GL2–HD1 forms non-covalent dimers (GL2–HD1)₂ in a concentration-dependent manner, affording ∼50% of the dimers at 1mmoldm⁻³ concentration.