Structure of the Human Telomere in K + Solution: A Stable Basket-Type G-Quadruplex with Only Two G-Tetrad Layers - Archive ouverte HAL Accéder directement au contenu
Article Dans Une Revue Journal of the American Chemical Society Année : 2009

Structure of the Human Telomere in K + Solution: A Stable Basket-Type G-Quadruplex with Only Two G-Tetrad Layers

Résumé

Previously, it has been reported that human telomeric DNA sequences could adopt in different experimental conditions four different intramolecular G-quadruplexes each involving three G-tetrad layers, namely, Na(+) solution antiparallel-stranded basket form, K(+) crystal parallel-stranded propeller form, K(+) solution (3 + 1) Form 1, and K(+) solution (3 + 1) Form 2. Here we present a new intramolecular G-quadruplex adopted by a four-repeat human telomeric sequence in K(+) solution (Form 3). This structure is a basket-type G-quadruplex with only two G-tetrad layers: loops are successively edgewise, diagonal, and edgewise; glycosidic conformations of guanines are syn x syn x anti x anti around each tetrad. Each strand of the core has both a parallel and an antiparallel adjacent strands; there are one narrow, one wide, and two medium grooves. Despite the presence of only two G-tetrads in the core, this structure is more stable than the three-G-tetrad intramolecular G-quadruplexes previously observed for human telomeric sequences in K(+) solution. Detailed structural elucidation of Form 3 revealed extensive base pairing and stacking in the loops capping both ends of the G-tetrad core, which might explain the high stability of the structure. This novel structure highlights the conformational heterogeneity of human telomeric DNA. It establishes a new folding principle for G-quadruplexes and suggests new loop sequences and structures for targeting in human telomeric DNA.

Dates et versions

hal-02122499 , version 1 (07-05-2019)

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Kah Wai Lim, Samir Amrane, Serge Bouaziz, Weixin Xu, Yuguang Mu, et al.. Structure of the Human Telomere in K + Solution: A Stable Basket-Type G-Quadruplex with Only Two G-Tetrad Layers. Journal of the American Chemical Society, 2009, 131 (12), pp.4301-4309. ⟨10.1021/ja807503g⟩. ⟨hal-02122499⟩
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