title: Structure of a two-G-tetrad intramolecular G-quadruplex formed by a variant human telomeric sequence in K+ solution: insights into the interconversion of human telomeric G-quadruplex structures.
abstract: Human telomeric DNA G-quadruplex has been considered as an attractive target for cancer therapeutic intervention. The telomeric sequence shows intrinsic structure polymorphism. Here we report a novel intramolecular G-quadruplex structure formed by a variant human telomeric sequence in K(+) solution. This sequence forms a basket-type intramolecular G-quadruplex with only two G-tetrads but multiple-layer capping structures formed by loop residues. While it is shown that this structure can only be detected in the specifically truncated telomeric sequences without any 5'-flanking residues, our results suggest that this two-G-tetrad conformation is likely to be an intermediate form of the interconversion of different telomeric G-quadruplex conformations.
authors: College of Pharmacy, The University of Arizona, Tucson, AZ 85721, USA.
authors: Zhenjiang
authors: Z
authors: Zhang
authors: Jixun
authors: J
authors: Dai
authors: Elizabeth
authors: E
authors: Veliath
authors: Roger A
authors: RA
authors: Jones
authors: Danzhou
authors: D
authors: Yang
mesh_terms: D002942:Circular Dichroism; D004247:DNA / Q000737:chemistry*; D054856:G-Quadruplexes; D006801:Humans; D008958:Models, Molecular; D019906:Nuclear Magnetic Resonance, Biomolecular; D011188:Potassium / Q000737:chemistry*; D011522:Protons; D016615:Telomere / Q000737:chemistry*
chemical_list: D011522:Protons; D004247:DNA; D011188:Potassium