Two-repeat Tetrahymena telomeric d(TGGGGTTGGGGT) Sequence interconverts between asymmetric dimeric G-quadruplexes in solution.

ABSTRACT: Recently, the two-repeat human telomeric d(TAGGGTTAGGGT) sequence has been shown to form interconverting parallel and antiparallel G-quadruplex structures in solution. Here, we examine the structures formed by the two-repeat Tetrahymena telomeric d(TGGGGTTGGGGT) sequence, which differs from the human sequence only by one G-for-A replacement in each repeat. We show by NMR that this sequence forms two novel G-quadruplex structures in Na+-containing solution. Both structures are asymmetric, dimeric G-quadruplexes involving a core of four stacked G-tetrads and two edgewise loops. The adjacent strands of the G-tetrad core are alternately parallel and antiparallel. All G-tetrads adopt syn.syn.anti.anti alignments, which occur with 5'-syn-anti-syn-anti-3' alternations along G-tracks. In the first

SUBMITTER: Phan AT 

PROVIDER: S-EPMC4690524 | biostudies-literature | 2004 Apr

REPOSITORIES: biostudies-literature