A novel synthetic route to generate oligonucleotides containing a monoadduct or γ-interstrand crosslink from a DNA-distorting mitomycin is presented. The oligonucleotides are thoroughly characterized using mass and circular dichroism spectroscopy as well as thermal denaturation studies. The structure of this novel crosslinked duplex is compared with that of less-distorting mitomycin ICLs using Molecular Dynamics simulations.

Mitomycin C (MC) is a powerful chemotherapy agent currently used in clinics for the treatment of various types of cancer. MC functions by inhibiting cellular growth through the formation of cytotoxic interstrand crosslinks (ICLs). These ICLs induced by MC have minimal impact on the DNA backbone, preserving its B-DNA structure. Recent research suggests that the cellular machinery recognizes and repairs ICLs differently based on their specific structure. To better understand how DNA distortion caused by MC ICLs influences cytotoxic effects, Herein, a novel mitomycin ICL is synthiesized that, unlike MC, significantly distorts DNA and widens the minor groove. This work outlines the synthesis of oligonucleotides bearing a single monoadduct or a single ICL of this new MC derivative at a defined position. Such substrates are widely used for investigations into biological processes such as DNA damage/repair studies. The monoadducted and crosslinked oligonucleotides are thoroughly characterized using various techniques, including enzymatic digestion to nucleosides, mass and circular dichroism spectroscopy, as well as thermal denaturation studies. Furthermore, the structure of this novel crosslinked duplex is compared with that of less-distorting mitomycin ICLs using Molecular Dynamics simulations.