Probing transient Hoogsteen hydrogen bonds in canonical duplex DNA using NMR relaxation dispersion and single-atom substitution.

ABSTRACT: Nucleic acids transiently morph into alternative conformations that can be difficult to characterize at the atomic level by conventional methods because they exist for too little time and in too little abundance. We recently reported evidence for transient Hoogsteen (HG) base pairs in canonical B-DNA based on NMR carbon relaxation dispersion. While the carbon chemical shifts measured for the transient state were consistent with a syn orientation for the purine base, as expected for A(syn)•T(anti) and G(syn)•C(+)(anti) HG base pairing, HG type hydrogen bonding could only be inferred indirectly. Here, we develop two independent approaches for directly probing transient changes in N-H···N hydrogen bonds and apply them to the characterization of transient Hoogsteen type hydrogen bonds in canon

SUBMITTER: Nikolova EN 

PROVIDER: S-EPMC3791138 | biostudies-literature | 2012 Feb

REPOSITORIES: biostudies-literature