Nanometre distance measurements with EPR using different spin probes.
Lead Research Organisation:
University of St Andrews
Department Name: Chemistry
Abstract
Pulse electron paramagnetic resonance (EPR) spectroscopy is an emerging technique for long range distance determination. Sparse long-range distances are very valuable for understanding structure and flexibility of complex nanostructures. Specifically, using an EPR method called PELDOR (pulsed electron-electron double resonance) or DEER (double electron-electron resonance), it is possible to reliably measure distances of up to 10 nm and beyond between two paramagnetic centres in the system studied. These paramagnetic centres can be native metal ions or radical cofactors, but most commonly they are deliberately introduced by a technique called site-directed spin-labelling.
This project aims to explore different types of paramagnetic centres to be employed a spin labels and to firmly establish best practices for the choice of labels especially with respect to the amount of information that can be extracted from samples labelled with several spectroscopically distinct probes (orthogonal labelling). To this end chemical models bearing paramagnetic metal centres and organic radicals will be employed to benchmark the metal nitroxide distance measurements using different methods based on excitation with two frequencies (PELDOR) or relaxation based methods (RIDME). In a second step systems bearing multiple spin centres will be scrutinised. This will be extremely valuable for applications in multimeric systems in which several spin-labelled monomers assemble to the functional unit. In particular addressing specific distances within the complex structure will be a huge gain in information. These model studies will be backed up by numeric simulations and the outcome is envisioned to be transferred to a model protein multimer. This approach will add to the armoury of structural EPR techniques with the long term aim of identifying structural changes in systems not accessible with current methods.
This project aims to explore different types of paramagnetic centres to be employed a spin labels and to firmly establish best practices for the choice of labels especially with respect to the amount of information that can be extracted from samples labelled with several spectroscopically distinct probes (orthogonal labelling). To this end chemical models bearing paramagnetic metal centres and organic radicals will be employed to benchmark the metal nitroxide distance measurements using different methods based on excitation with two frequencies (PELDOR) or relaxation based methods (RIDME). In a second step systems bearing multiple spin centres will be scrutinised. This will be extremely valuable for applications in multimeric systems in which several spin-labelled monomers assemble to the functional unit. In particular addressing specific distances within the complex structure will be a huge gain in information. These model studies will be backed up by numeric simulations and the outcome is envisioned to be transferred to a model protein multimer. This approach will add to the armoury of structural EPR techniques with the long term aim of identifying structural changes in systems not accessible with current methods.
Organisations
Publications
Wort J
(2020)
Electron Paramagnetic Resonance - Volume 27
Giannoulis A
(2017)
Monitoring Complex Formation by Relaxation-Induced Pulse Electron Paramagnetic Resonance Distance Measurements.
in Chemphyschem : a European journal of chemical physics and physical chemistry
Giannoulis A
(2018)
Orientation selection in high-field RIDME and PELDOR experiments involving low-spin CoII ions.
in Physical chemistry chemical physics : PCCP
Oranges M
(2022)
Pulse Dipolar Electron Paramagnetic Resonance Spectroscopy Reveals Buffer-Modulated Cooperativity of Metal-Templated Protein Dimerization
in The Journal of Physical Chemistry Letters
Studentship Projects
Project Reference | Relationship | Related To | Start | End | Student Name |
---|---|---|---|---|---|
EP/N509759/1 | 01/10/2016 | 30/09/2021 | |||
1792319 | Studentship | EP/N509759/1 | 01/10/2016 | 03/06/2020 | Maria Oranges |
Description | During this funded period, my research has been focused on the development of methodologies to characterize the structure of biomolecules. The technique use is the Electron paramagnetic ressonance (EPR) spectroscopy which allows to measure distances between paramagnetic centers (metal ion, cofactors etc.) in the system. New routes to study multimerization in biomolecules and retrieve angular constrains between the paramagnetic centers have been developed. |
Exploitation Route | These methodologies as above, can be applied in structural biology to investigate the structure and conformational equilibria of biomolecules to understand the mechanisms of the functions of these systems. |
Sectors | Other |
Description | Multi-Frequency Orientation Selective (OS) RIDME on biological systems. |
Amount | € 1,250 (EUR) |
Organisation | German Academic Exchange Service (DAAD) |
Sector | Academic/University |
Country | United States |
Start | 08/2019 |
End | 09/2019 |
Description | Supramolecular structure predictions validated from sparse experimental data |
Amount | £454,684 (GBP) |
Funding ID | EP/X016455/1 |
Organisation | Engineering and Physical Sciences Research Council (EPSRC) |
Sector | Public |
Country | United Kingdom |
Start | 11/2022 |
End | 10/2025 |