Recognition and repair of trans-syn II cyclobutane thymine dimer by mammalian excision nuclease indicate that the affinities of damage sensors do not dictate the repair efficiency Public Deposited

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  • March 21, 2019
  • Hutsell, Stephanie Quinn
    • Affiliation: School of Medicine, Department of Biochemistry and Biophysics
  • The trans-syn cyclobutane pyrimidine dimer is a minor, but biologically significant ultraviolet photoproduct that is produced primarily in single-strand DNA. The only known repair system for this lesion is nucleotide excision repair. In this study I investigated the recognition and repair of the trans-syn cyclobutane thymine dimer by mammalian excision nuclease. I find that the trans-syn cyclobutane thymine dimer is recognized by RPA, XPA, and XPC damage sensor proteins with high specificity comparable to that of the [6-4] photoproduct; however, this lesion is excised by the mammalian excision nuclease with efficiency comparable to that of the poorly recognized cis-syn cyclobutane pyrimidine dimer. These data suggest that kinetic factors, after the initial damage recognition step, play a major role in the overall catalytic proficiency of the mammalian excision nuclease.
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  • Sancar, Aziz
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  • University of North Carolina at Chapel Hill
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