Syntheses of DNA duplexes that contain a N⁴C-alkyl-N⁴C interstrand cross-link.

This unit describes a simple procedure for preparing short DNA duplexes that contain a single N(4)C-alkyl-N(4)C interstrand cross-link. The synthesis is carried out on an automated DNA synthesizer using standard phosphoramidite chemistry. The cross-link is introduced during the synthesis of the duplex. The method can be used to prepare milligram quantities of cross-linked duplexes suitable for physical studies and for the preparation of larger DNA molecules that can be used as substrates to study DNA repair in whole cell extracts and in living cells in culture.