Year: 2019
Type: article
Abstract: Base-pair mismatch can relieve mechanical stress in highly strained DNA molecules, but how it affects their kinetic stability is not known. Using single-molecule fluorescence resonance energy transfer, we measured the lifetimes of tightly bent DNA loops with and without base-pair mismatch. Surprisingly, for loops captured by stackable sticky ends which leave single-stranded DNA breaks (or nicks) upon annealing, the mismatch decreased the loop lifetime despite reducing the overall bending stress, and the decrease was largest when the mismatch was placed at the DNA midpoint. These findings suggest that base-pair mismatch increases bending stress at the opposite side of the loop through an allosteric mechanism known as cooperative kinking. Based on this mechanism, we present a three-state model that explains the apparent dichotomy between thermodynamic and kinetic stability.
Source: Physical Review Letters
Authors: Jiyoun Jeong, Harold D. Kim
Institution: Georgia Institute of Technology
Language: English
Subfield: Molecular Biology
Domain: Life Sciences
Open Access status: green
OpenAlex ID: W2908239666