Despite the importance of chemotherapeutic agents that form DNA interstrand crosslinks (ICLs) during cancer therapy, it remains poorly understood how ICLs are repaired. Present evidence suggests that while the main ICL repair pathway in mammals depends on replication and homologous recombination at least one replication-independent minor pathway exists.

The limited availability of defined ICL substrates is the major impediment to studying the ICL repair mechanisms. To overcome this limitation we have developed strategies for the de novo synthesis of different analogs of the clinically-relevant nitrogen mustard (NM) ICLs to provide tools for biochemical studies. In our approach two “crosslink precursors” with reactive aldehyde groups are incorporated into complementary strands of DNA using solid phase synthesis and crosslink formation is induced by a double reductive amination.

In this pproject we will expand the scope of this strategy by synthesizing new crosslink precursors and using them to generate a range of relevant NM ICLs analogs by means of different amines. Moreover, we will use NMR techniques to structurally characterize various NM ICL mimics. The combination of chemical and structural approaches will provide well defined and well characterized substrates for biochemical and cell biological studies of ICL repair.