The catalytic power of uracil DNA glycosylase in the opening of thymine base pairs

A study measured deoxyribonucleic acid (DNA) base pair opening and closing rates in the absence and presence of uracil DNA glycolase (UNG) for a series of increasingly destabilized thymine base pairs (TX) that contain one, two, or three hydrogen bonds. Comparison of the measured opening rates ([k.sub.op]) for each [T.sup.6]X base pair in the free and UNG-bound DNA indicates that UNG does not actively accelerate base pair opening.