Low-frequency vibrational modes in G-quadruplexes reveal the mechanical properties of nucleic acids

• Published in: Physical chemistry chemical physics : PCCP Vol. 23; no. 23; pp. 1325 - 1326
• Main Authors: González-Jiménez, Mario, Ramakrishnan, Gopakumar, Tukachev, Nikita V, Senn, Hans M, Wynne, Klaas
• Format: Journal Article
• Language: English
• Published: Cambridge Royal Society of Chemistry 21.06.2021; The Royal Society of Chemistry
• Subjects: Charge transfer; Chemistry; Deoxyribonucleic acid; DNA; Gene expression; Mechanical properties; Nucleic acids; Spectrum analysis; Stiffness; Vibrational spectra
• ISSN: 1463-9076; 1463-9084; 1463-9084
• DOI: 10.1039/d0cp05404f

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. Low-frequency vibrations play an essential role in biomolecular processes involving DNA such as gene expression, charge transfer, drug intercalation, and DNA-protein recognition.