Intercalation (chemistry)
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Intercalation is a term used in host-guest chemistry for the reversible inclusion of a molecule (or group) between two other molecules (or groups). The host molecules usually comprise some form of periodic network. Intercalation is found in DNA intercalation and in graphite intercalation compounds.
[edit] DNA intercalation
A large class of molecules intercalates into DNA - in the space between two adjacent base pairs. These molecules are mostly polycyclic, aromatic, and planar, and therefore often make good nucleic acid stains. Intensively studied DNA intercalators include ethidium, proflavin, daunomycin, doxorubicin, and thalidomide. DNA intercalators are used in chemotherapeutic treatment of concern to inhibit DNA replication in rapidly growing cancer cells.
In order for an intercalator to fit between base pairs, the latter must separate by over 0.3 nanometre, inducing local structural changes to the DNA strand, such as unwinding of the double helix and lengthening of the DNA strand. These structural modifications lead to functional changes, often to the inhibition of transcription and replication processes, which makes intercalators potent mutagens. DNA intercalators are often carcinogenic, such as benzopyrene diol epoxide, bisbenzimide, aflatoxin, or ethidium bromide.
