Unprecedented hour-long residence time of a cation in a left-handed G-quadruplex.

ABSTRACT: Cations are critical for the folding and assembly of nucleic acids. In G-quadruplex structures, cations can bind between stacked G-tetrads and coordinate with negatively charged guanine carbonyl oxygens. They usually exchange between binding sites and with the bulk in solution with time constants ranging from sub-millisecond to seconds. Here we report the first observation of extremely long-lived K⁺ and NH₄ ⁺ ions, with an exchange time constant on the order of an hour, when coordinated at the center of a left-handed G-quadruplex DNA. A single-base mutation, that switched one half of the structure from left- to right-handed conformation resulting in a right-left hybrid G-quadruplex, was shown to remove this long-lived behaviour of the central cation.

SUBMITTER: Winnerdy FR 

PROVIDER: S-EPMC8153214 | biostudies-literature | 2021 Apr

REPOSITORIES: biostudies-literature