Dynamics of Nucleic Acids at Room Temperature Revealed by Pulsed EPR Spectroscopy. Issue 33 (13th July 2018)

• Record Type: Journal Article
• Authors: Gränz, Markus; Erlenbach, Nicole; Spindler, Philipp; Gophane, Dnyaneshwar B.; Stelzl, Lukas S.; Sigurdsson, Snorri Th.; Prisner, Thomas F.
• Is Part Of: Angewandte Chemie international edition. Volume 57:Issue 33(2018)
• Page Start: 10540
• Page End: 10543
• Publication Date: 2018-07-13
• Subjects: conformational dynamics -- DEER spectroscopy -- DNA -- EPR spectroscopy -- PELDOR spectroscopy; Chemistry -- Periodicals; 540
• DOI: 10.1002/anie.201803682
• Languages: English
• ISSNs: 1433-7851

Abstract

Abstract: The investigation of the structure and conformational dynamics of biomolecules under physiological conditions is challenging for structural biology. Although pulsed electron paramagnetic resonance (like PELDOR) techniques provide long‐range distance and orientation information with high accuracy, such studies are usually performed at cryogenic temperatures. At room temperature (RT) PELDOR studies are seemingly impossible due to short electronic relaxation times and loss of dipolar interactions through rotational averaging. We incorporated the rigid nitroxide spin label Ç into a DNA duplex and immobilized the sample on a solid support to overcome this limitation. This enabled orientation‐selective PELDOR measurements at RT. A comparison with data recorded at 50 K revealed averaging of internal dynamics, which occur on the ns time range at RT. Thus, our approach adds a new method to study structural and dynamical processes at physiological temperature in the <10 μs time range with atomistic resolution. Abstract : When a rigid nitroxide spin label was incorporated into a DNA duplex and the sample was immobilized on a solid support, orientation‐selective pulsed EPR measurements were possible at room temperature. Comparison with the low‐temperature (50 K) PELDOR data and MD simulations revealed averaging of the fast internal dynamics on the ns time scale at room temperature. Thus, this new approach allows the study of structural and dynamical processes at physiological temperature with atomistic resolution.