Project: We have developed a new strategy that enables the synthesis of defined site-specific crosslinks in high yields and purity and provides a valuable tool for biochemical and cell biological studies of ICL repair. This crosslinks mimic the interstrand crosslinks formed by the clinically important nitrogen mustards. We were able to synthesize different crosslinks having the same length of NM ICL and also longer ones, which are supposedly less distorting. We are currently investigating the spatial geometry of NM ICL analogues with different bridges length to better understand the importance of the structure of the lesion in the recognition step. We will characterize the 3D structure of one of the crosslink analogs using high resolution NMR, which used in combination with MD studies performed in collaboration with the Simmerling lab will allow the comparison of the salient features of our ICLs mimics with their natural counterparts.