Disclosed herein are methods of destabilizing double-stranded nucleic acid hybridization using an enzyme comprising DNA N-glycosylase activity. Also disclosed herein is the detection of a double-stranded target DNA wherein the hybridization of duplex strands has been at least partially disrupted thereby permitting invasion of a probe strand. Also disclosed herein are methods of using an enzyme comprising DNA N-glycosylase activity to generate single-stranded circular nucleic acids.