Locally disrupted base pairing

In DNA replication and other processes, the two strands of the double helix must be separated from each other, at least in a local region. The two strands of a DNA helix readily come apart when the hydrogen bonds between base pairs are disrupted. In the laboratory, the double helix can be disrupted by heating a solution of DNA or by adding acid or alkali to ionize its bases. The dissociation of the double helix is called melting because it occurs abruptly at a certain temperature. The melting temperature (Tj ) is defined as the... 

To test this sensitivity of photoinduced quenching to perturbations in the intervening base pair stack, an assembly was prepared containing an intervening CA base mismatch which disrupts locally the /r-stack between the donor and acceptor. We observed that the yield of CT was reduced in the DNA... 

Locally disrupted base pairing can take a number of different forms. 

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