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A novel chair-type G-quadruplex formed by a Bombyx mori telomeric sequence

Recently, the human telomeric d[TAGGG(TTAGGG)(3)] sequence has been shown to form in K(+) solution an intramolecular (3+1) G-quadruplex structure, whose G-tetrad core contains three strands oriented in one direction and the fourth in the opposite direction. Here we present a study on the structure o...

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Detalles Bibliográficos
Autores principales: Amrane, Samir, Ang, Rita Wan Lin, Tan, Zhong Ming, Li, Chun, Lim, Joefina Kim Cheow, Lim, Jocelyn Mei Wen, Lim, Kah Wai, Phan, Anh Tuân
Formato: Texto
Lenguaje:English
Publicado: Oxford University Press 2009
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2647293/
https://www.ncbi.nlm.nih.gov/pubmed/19103662
http://dx.doi.org/10.1093/nar/gkn990
Descripción
Sumario:Recently, the human telomeric d[TAGGG(TTAGGG)(3)] sequence has been shown to form in K(+) solution an intramolecular (3+1) G-quadruplex structure, whose G-tetrad core contains three strands oriented in one direction and the fourth in the opposite direction. Here we present a study on the structure of the Bombyx mori telomeric d[TAGG(TTAGG)(3)] sequence, which differs from the human counterpart only by one G deletion in each repeat. We found that this sequence adopted multiple G-quadruplex structures in K(+) solution. We have favored a major G-quadruplex form by a judicious U-for-T substitution in the sequence and determined the folding topology of this form. We showed by NMR that this was a new chair-type intramolecular G-quadruplex which involved a two-layer antiparallel G-tetrad core and three edgewise loops. Our result highlights the effect of G-tract length on the folding topology of G-quadruplexes, but also poses the question of whether a similar chair-type G-quadruplex fold exists in the human telomeric sequences.