Synthesis and properties of oligonucleotides carrying cryptolepine derivatives.

A carboxy derivative of the antimalarial cytotoxic drug cryptolepine was introduced into synthetic oligonucleotides by reaction of the carboxy derivative of cryptolepine with oligonucleotides carrying an amino group either at the 3'- or at the 5'-end. Oligonucleotides carrying the cryptolepine derivative bind their complementary sequences with greater affinity than unmodified ones. When cryptolepine is attached to a polypyrimidine oligonucleotide designed to form a parallel triplex, the triplex shows none or weak stabilization.