The antimalarial and cytotoxic drug cryptolepine intercalates into DNA at cytosine-cytosine sites.
Lisgarten, J.N., Coll, M., Portugal, J., Wright, C.W., Aymami, J.(2002) Nat Struct Biol 9: 57-60
- PubMed: 11731803 
- DOI: https://doi.org/10.1038/nsb729
- Primary Citation of Related Structures:  
1K9G - PubMed Abstract: 
Cryptolepine, a naturally occurring indoloquinoline alkaloid used as an antimalarial drug in Central and Western Africa, has been found to bind to DNA in a formerly unknown intercalation mode. Evidence from competition dialysis assays demonstrates that cryptolepine is able to bind CG-rich sequences containing nonalternating CC sites. Here we show that cryptolepine interacts with the CC sites of the DNA fragment d(CCTAGG)(2) in a base-stacking intercalation mode. This is the first DNA intercalator complex, from approximately 90 solved by X-ray crystallography, to bind a nonalternating (pyrimidine-pyrimidine) DNA sequence. The asymmetry of the drug induces a perfect stacking with the asymmetric site, allowing for the stability of the complex in the absence of hydrogen bonding interactions. The crystal structure of this antimalarial drug-DNA complex provides evidence for the first nonalternating intercalation and, as such, provides a basis for the design of new anticancer or antimalarial drugs.
Organizational Affiliation: 
Institut de Biologia Molecular de Barcelona, C.S.I.C., Jordi Girona 18, 08034 Barcelona, Spain.