Structure of the intramolecular human telomeric G-quadruplex in potassium solution: a novel adenine triple formation.

ABSTRACT: We report the NMR solution structure of the intramolecular G-quadruplex formed in human telomeric DNA in K(+). The hybrid-type telomeric G-quadruplex consists of three G-tetrads linked with mixed parallel-antiparallel G-strands, with the bottom two G-tetrads having the same G-arrangement (anti:anti:syn:anti) and the top G-tetrad having the reversed G-arrangement (syn:syn:anti:syn). The three TTA loop segments adopt different conformations, with the first TTA assuming a double-chain-reversal loop conformation, and the second and third TTA assuming lateral loop conformations. The NMR structure is very well defined, including the three TTA loops and the two flanking sequences at 5'- and 3'-ends. Our study indicates that the three loop regions interact with the core G-tetrads in a specific way

SUBMITTER: Dai J 

PROVIDER: S-EPMC1874667 | biostudies-literature | 2007

REPOSITORIES: biostudies-literature