Artefact suppression in 5-pulse double electron electron resonance for distance distribution measurements

2017 ◽  
Vol 19 (24) ◽  
pp. 15766-15779 ◽  
Author(s):  
Frauke D. Breitgoff ◽  
Janne Soetbeer ◽  
Andrin Doll ◽  
Gunnar Jeschke ◽  
Yevhen O. Polyhach
Keyword(s):  
Membrane Proteins ◽  
Data Processing ◽  
Spin Relaxation ◽  
Electron Spin ◽  
Distance Distribution ◽  
Spectral Purity ◽  
Electron Resonance ◽  
Electron Spin Relaxation ◽  
Double Electron ◽  
Double Electron Electron Resonance

Long dipolar evolution data for membrane proteins with exponential electron spin relaxation can be achieved with spectral purity sufficient for robust data processing.

scholarly journals The decay of the refocused Hahn echo in double electron–electron resonance (DEER) experiments

2021 ◽  
Vol 2 (1) ◽  
pp. 161-173
Author(s):  
Thorsten Bahrenberg ◽  
Samuel M. Jahn ◽  
Akiva Feintuch ◽  
Stefan Stoll ◽  
Daniella Goldfarb
Keyword(s):  
Electron Spin ◽  
Large Scale ◽  
Pulse Sequence ◽  
Spin Dynamics ◽  
Spin Echo ◽  
Sequence Length ◽  
Flip Flop ◽  
Electron Resonance ◽  
Double Electron ◽  
Double Electron Electron Resonance

Abstract. Double electron–electron resonance (DEER) is a pulse electron paramagnetic resonance (EPR) technique that measures distances between paramagnetic centres. It utilizes a four-pulse sequence based on the refocused Hahn spin echo. The echo decays with increasing pulse sequence length 2(τ1+τ2), where τ1 and τ2 are the two time delays. In DEER, the value of τ2 is determined by the longest inter-spin distance that needs to be resolved, and τ1 is adjusted to maximize the echo amplitude and, thus, sensitivity. We show experimentally that, for typical spin centres (nitroxyl, trityl, and Gd(III)) diluted in frozen protonated solvents, the largest refocused echo amplitude for a given τ2 is obtained neither at very short τ1 (which minimizes the pulse sequence length) nor at τ1=τ2 (which maximizes dynamic decoupling for a given total sequence length) but rather at τ1 values smaller than τ2. Large-scale spin dynamics simulations based on the coupled cluster expansion (CCE), including the electron spin and several hundred neighbouring protons, reproduce the experimentally observed behaviour almost quantitatively. They show that electron spin dephasing is driven by solvent protons via the flip-flop coupling among themselves and their hyperfine couplings to the electron spin.

Direct Observation of Chain Lengths and Conformations in Oligofluorene Distributions from Controlled Polymerization by Double Electron-Electron Resonance

2019 ◽  
Author(s):  
Dennis Bücker ◽  
Annika Sickinger ◽  
Julian D. Ruiz Perez ◽  
Manuel Oestringer ◽  
Stefan Mecking ◽  
...  
Keyword(s):  
Chain Length ◽  
Length Distribution ◽  
Catalyst System ◽  
Chain Conformation ◽  
Controlled Polymerization ◽  
Chain Length Distribution ◽  
Electron Resonance ◽  
Double Electron ◽  
The Individual ◽  
Double Electron Electron Resonance

Synthetic polymers are mixtures of different length chains, and their chain length and chain conformation is often experimentally characterized by ensemble averages. We demonstrate that Double-Electron-Electron-Resonance (DEER) spectroscopy can reveal the chain length distribution, and chain conformation and flexibility of the individual n-mers in oligo-(9,9-dioctylfluorene) from controlled Suzuki-Miyaura Coupling Polymerization (cSMCP). The required spin-labeled chain ends were introduced efficiently via a TEMPO-substituted initiator and chain terminating agent, respectively, with an in situ catalyst system. Individual precise chain length oligomers as reference materials were obtained by a stepwise approach. Chain length distribution, chain conformation and flexibility can also be accessed within poly(fluorene) nanoparticles.

In-Cell Double Electron–Electron Resonance at Nanomolar Protein Concentrations

2021 ◽  
pp. 3679-3684
Author(s):  
Svetlana Kucher ◽  
Christina Elsner ◽  
Mariya Safonova ◽  
Stefano Maffini ◽  
Enrica Bordignon
Keyword(s):  
Electron Resonance ◽  
Double Electron ◽  
Double Electron Electron Resonance
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