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

作者：Amrane Samir; Ang Rita Wan Lin; Tan Zhong Ming; Li Chun; Lim Joefina Kim Cheow; Lim Jocelyn Mei Wen; Lim Kah Wai; Phan Anh Tuan^*

来源：Nucleic Acids Research, 2009, 37(3): 931-938.

DOI：10.1093/nar/gkn990

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(TTAG G)(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.

• 出版日期2009-2
• 单位南阳理工学院