Incorporation of 5-hydroxycytosine (5OHdC) into DNA leads to C to T transition mutations. Crystal structure of 5OHdC in DNA with polymerase revealed that the lesion stabilizes the incoming dGMP via canonical base pairing. However the incorporation of dAMP opposite the lesion leads to destabilizing unstacking. Here we describe studies of the modified DNA, where 5OHdC is base paired with dG and dA. High resolution NMR spectroscopy reveals that the 5OHdC�dG is less stable than its Watson-Crick partner dC�dG, although it does not differ significantly in structure. When mismatched with dA, 5OHdC is displaced into the major groove. The structural and thermodynamic properties of the modified base pairs could provide for a mechanism of recognition by DNA polymerases and repair enzymes.

Characterization of 5-hydroxycytosine opposite guanine and adenine in DNA

246th National Meeting (2013)

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.