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Updated: Jun 22, 2026

Atomic Force Microscopy Investigations of DNA Lesion Recognition in Nucleotide Excision Repair
Published on: May 24, 2017
Lambda exonuclease digestion of CGG trinucleotide repeats
R S Conroy1, A P Koretsky, J Moreland
1Laboratory of Functional and Molecular Imaging, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD, 20892, USA. conroyri@mail.nih.gov
Abstract:
Fragile X syndrome and other trinucleotide diseases are characterized by an elongation of a repeating DNA triplet. The ensemble-averaged lambda exonuclease digestion rate of different substrates, including one with an elongated FMR1 gene containing 120 CGG repeats, was measured using absorption and fluorescence spectroscopy. By use of magnetic tweezers sequence-dependent digestion rates and pausing was measured for individual lambda exonucleases. Within the triplet repeats a lower average and narrower distribution of rates and a higher frequency of pausing was observed.
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