Molecular recognition of nucleic acid by small molecules. Binding affinity and structural specificity of bis(methidium)spermine

Nucleic acids are biologically important receptors sufficiently characterized to encourage the syntheses of site specific probes. Molecules capable of binding to nucleic acid templates and interfering with processes in which nucleic acids participate are important in both antibiotic and cancer chemotherapy. Some drugs bind to nucleic acids by intercalation, the insertion of a flat molecule between the base pairs of a double helix. In the absence of unfavorable entropic or steric constraints, an increase in binding affinity and sequence specificity would be expected for polyintercalators which are capable of inserting two or more intercalating units into the nucleic acid double helix.