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Updated: Jun 20, 2026

Single-Molecule Fluorescence Visualization of DNA Polymerase Dynamics at G-Quadruplexes
Published on: April 4, 2025
A G-rich sequence within the c-kit oncogene promoter forms a parallel G-quadruplex having asymmetric G-tetrad
Shang-Te Danny Hsu1, Peter Varnai, Anthony Bugaut
1University Chemical Laboratory, University of Cambridge, Lensfield Road, Cambridge, CB2 1EW, United Kingdom.
Abstract:
Guanine-rich DNA sequences with the ability to form quadruplex structures are enriched in the promoter regions of protein-coding genes, particularly those of proto-oncogenes. G-quadruplexes are structurally polymorphic and their folding topologies can depend on the sample conditions. We report here on a structural study using solution state NMR spectroscopy of a second G-quadruplex-forming motif (c-kit2) that has been recently identified in the promoter region of the c-kit oncogene. In the presence of potassium ions, c-kit2 exists as an ensemble of structures that share the same parallel-stranded propeller-type conformations. Subtle differences in structural dynamics have been identified using hydrogen-deuterium exchange experiments by NMR spectroscopy, suggesting the coexistence of at least two structurally similar but dynamically distinct substates, which undergo slow interconversion on the NMR timescale.
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