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Updated: Nov 2, 2025

Single-molecule Manipulation of G-quadruplexes by Magnetic Tweezers
Published on: September 19, 2017
Low-frequency vibrational modes in G-quadruplexes reveal the mechanical properties of nucleic acids
Mario González-Jiménez1, Gopakumar Ramakrishnan, Nikita V Tukachev
1School of Chemistry, University of Glasgow, Glasgow, G12 8QQ, UK. klaas.wynne@glasgow.ac.uk.
Abstract:
Low-frequency vibrations play an essential role in biomolecular processes involving DNA such as gene expression, charge transfer, drug intercalation, and DNA-protein recognition. However, understanding the vibrational basis of these mechanisms relies on theoretical models due to the lack of experimental evidence. Here we present the low-frequency vibrational spectra of G-quadruplexes (structures formed by four strands of DNA) and B-DNA characterized using femtosecond optical Kerr-effect spectroscopy. Contrary to expectation, we found that G-quadruplexes show several strongly underdamped delocalized phonon-like modes that have the potential to contribute to the biology of the DNA at the atomic level. In addition, G-quadruplexes present modes at a higher frequency than B-DNA demonstrating that changes in the stiffness of the molecule alter its gigahertz to terahertz vibrational profile.
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