Structure and Conformational Dynamics of a Stacked Dimeric G‑Quadruplex Formed by the Human CEB1 Minisatellite Michael Adrian Ding Jie Ang Christopher J. Lech Brahim Heddi Alain Nicolas Anh Tuân Phan 10.1021/ja4125274.s001 https://acs.figshare.com/articles/journal_contribution/Structure_and_Conformational_Dynamics_of_a_Stacked_Dimeric_G_Quadruplex_Formed_by_the_Human_CEB1_Minisatellite/2302123 CEB1 is a highly polymorphic human minisatellite. In yeast, the size variation of CEB1 tandem arrays has been associated with the capacity of the motif to form G-quadruplexes. Here we report on the NMR solution structure of a G-quadruplex formed by the CEB1 DNA G-rich fragment d­(AGGGGGGAGGGAGGGTGG), harboring several G-tracts including one with six continuous guanines. This sequence forms a dimeric G-quadruplex involving the stacking of two subunits, each being a unique snapback parallel-stranded scaffold with three G-tetrad layers, three double-chain-reversal loops, and a V-shaped loop. The two subunits are stacked at their 5′-end tetrads, and multiple stacking rotamers may be present due to a high symmetry at the stacking interface. There is a conformational exchange in the millisecond time scale involving a swapping motion between two bases of the six-guanine tract. Our results not only add to the understanding of how the G-quadruplex formation in human minisatellite leads to genetic instability but also address the fundamental questions regarding stacking of G-quadruplexes and how a long continuous G-tract participates in the structure and conformational dynamics of G-quadruplexes. 2014-04-30 00:00:00 Conformational Dynamics NMR solution structure Human CEB 1 MinisatelliteCEB 1 size variation DNA CEB 1 tandem arrays millisecond time scale subunit sequence forms minisatellite loop