Photoswitchable Formation of a DNA Interstrand Cross‐Link by a Coumarin‐Modified Nucleotide |
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| Authors: | Mohammad Mojibul Haque Huabing Sun Shuo Liu Prof Yinsheng Wang Prof Xiaohua Peng |
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| Affiliation: | 1. Department of Chemistry and Biochemistry, University of Wisconsin Milwaukee, 3210 N. Cramer St., Milwaukee, WI 53211 (USA);2. Department of Chemistry, University of California Riverside, 332 Chemical Sciences Building, 501 Big Springs Road, Riverside, CA 92521‐0403 (USA) |
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| Abstract: | A coumarin‐modified pyrimidine nucleoside ( 1 ) has been synthesized using a CuI‐catalyzed click reaction and incorporated into oligodeoxynucleotides (ODNs). Interstrand cross‐links are produced upon irradiation of ODNs containing 1 at 350 nm. Cross‐linking occurs through a 2+2] cycloaddition reaction with the opposing thymidine, 2′‐deoxycytidine, or 2′‐deoxyadenosine. A much higher reactivity was observed with dT than dC or dA. Irradiation of the dT‐ 1 and dC‐ 1 cross‐linked products at 254 nm leads to a reversible ring‐opening reaction, while such phenomena were not observed with dA‐ 1 adducts. The reversible reaction is ultrafast and complete within 50–90 s. Consistent photoswitching behavior was observed over 6 cycles of irradiation at 350 nm and 254 nm. To the best of our knowledge, this is the first example of photoswitchable interstrand cross‐linking formation induced by a modified pyrimidine nucleoside. |
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| Keywords: | click chemistry cycloaddition DNA cross‐linking nucleosides photoswitch |
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