Separation of intra- and intermolecular contributions to the PELDOR signal
| Autor: | Jörn Plackmeyer, Philipp Schöps, Andriy Marko |
|---|---|
| Rok vydání: | 2016 |
| Předmět: |
Nuclear and High Energy Physics
Noise (signal processing) Chemistry Oscillation Intermolecular force Biophysics 02 engineering and technology 010402 general chemistry 021001 nanoscience & nanotechnology Condensed Matter Physics 01 natural sciences Biochemistry Resonance (particle physics) Signal Molecular physics 0104 chemical sciences law.invention Amplitude modulation Nuclear magnetic resonance law Intramolecular force 0210 nano-technology Electron paramagnetic resonance |
| Zdroj: | Journal of Magnetic Resonance. 269:70-77 |
| ISSN: | 1090-7807 |
| DOI: | 10.1016/j.jmr.2016.05.012 |
| Popis: | Pulsed Electron–electron Double Resonance (PELDOR) is commonly used to measure distances between native paramagnetic centers or spin labels attached to complex biological macromolecules. In PELDOR the energies of electron magnetic dipolar interactions are measured by analyzing the oscillation frequencies of the recorded time resolved signal. Since PELDOR is an ensemble method, the detected signal contains contributions from intramolecular, as well as intermolecular electron spin interactions. The intramolecular part of the signal contains the information about the structure of the studied molecules, thus it is very important to accurately separate intra- and intermolecular contributions to the total signal. This separation can become ambiguous, when the length of the PELDOR signal is not much longer than twice the oscillation period of the signal. In this work we suggest a modulation depth scaling method, which can use short PELDOR signals in order to extract the intermolecular contribution. Using synthetic data we demonstrate the advantages of the new approach and analyze its stability with regard to signal noise. The method was also successfully tested on experimental data of three systems measured at Q-Band frequencies, two model compounds in deuterated and protonated solvents and one biological sample, namely BetP. The application of the new method with an assigned value of the signal modulation depth enables us to determine the interspin distances in all cases. This is especially interesting for the model compound with an interspin distance of 5.2 nm in the protonated solvent and the biological sample, since an accurate separation of the intra- and intermolecular PELDOR signal contributions would be difficult with the standard approach in those cases. |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|
Full Text from ScienceDirect