Methylation of cytosine influences the DNA structure.

In the past decade it has become increasingly clear that DNA has the potential to adopt a variety of unusual secondary structures which deviate from the classical right-handed B-DNA form. Intrinsic properties of the DNA molecule (primary base sequence and base modifications, degree of supercoiling) determine whether such an unusual structure is possible. Environmental factors (like ionic strength or pH of the medium, temperature, solvent polarity, interactions with proteins or drugs) have a strong influence on whether the structure is actually formed or not.

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