Toward a designed, functioning genetic system with expanded-size base pairs: solution structure of the eight-base xDNA double helix.

ABSTRACT: We describe the NMR-derived solution structure of the double-helical form of a designed eight-base genetic pairing system, termed xDNA. The benzo-homologous xDNA design contains base pairs that are wider than natural DNA pairs by ca. 2.4 A (the width of a benzene ring). The eight component bases of this xDNA helix are A, C, G, T, xA, xT, xC, and xG. The structure was solved in aqueous buffer using 1D and 2D NMR methods combined with restrained molecular dynamics. The data show that the decamer duplex is right-handed and antiparallel, and hydrogen-bonded in a way analogous to that of Watson-Crick DNA. The sugar-phosphate backbone adopts a regular conformation similar to that of B-form DNA, with small dihedral adjustments due to the larger circumference of the helix. The grooves are much wid

SUBMITTER: Lynch SR 

PROVIDER: S-EPMC2519095 | biostudies-literature | 2006 Nov

REPOSITORIES: biostudies-literature