2KF7
Structure of a two-G-tetrad basket-type intramolecular G-quadruplex formed by human telomeric repeats in K+ solution (with G7-to-BRG substitution)
Summary for 2KF7
| Entry DOI | 10.2210/pdb2kf7/pdb |
| Related | 143D 1K8P 2AQY 2GKU 2JSK 2JSL 2JSM 2JSQ 2KF8 |
| Descriptor | HUMAN TELOMERE DNA (1 entity in total) |
| Functional Keywords | anticancer targets, human telomere, intramolecular g-quadruplexes, dna |
| Total number of polymer chains | 1 |
| Total formula weight | 7053.38 |
| Authors | Lim, K.W.,Amrane, S.,Bouaziz, S.,Xu, W.,Mu, Y.,Patel, D.J.,Luu, K.N.,Phan, A.T. (deposition date: 2009-02-12, release date: 2009-03-24, Last modification date: 2024-05-01) |
| Primary citation | Lim, K.W.,Amrane, S.,Bouaziz, S.,Xu, W.,Mu, Y.,Patel, D.J.,Luu, K.N.,Phan, A.T. Structure of the human telomere in K+ solution: a stable basket-type G-quadruplex with only two G-tetrad layers J.Am.Chem.Soc., 131:4301-4309, 2009 Cited by PubMed Abstract: 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. PubMed: 19271707DOI: 10.1021/ja807503g PDB entries with the same primary citation |
| Experimental method | SOLUTION NMR |
Structure validation
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