Q-Band Double Quantum Coherence ESR for Sensitive Nitroxide-Based Distance Measurements.

ABSTRACT: Recent advances in pulsed dipolar spectroscopy have driven the sensitivity of the technique to physiologically relevant concentrations and extended its applicability to more complex biological systems. In this work, we establish double quantum coherence (DQC) ESR at Q-band as a practical technique for distance measurements in doubly nitroxide-labeled proteins. We show that 8 ns π pulses provide efficient excitation of the double quantum transition at Q-band, though more accessible 12 and 16 ns pulses also yield strong signals. Additionally, we show that the field dependence of the DQC signal is sensitive to the relative orientation of the two g-tensor axes. With careful spectrometer tuning, signal-to-noise ratios greater than 100 were possible in just 11 min of acquisition for a dipolar ev

SUBMITTER: Mandato A 

PROVIDER: S-EPMC12278208 | biostudies-literature | 2025 Jul

REPOSITORIES: biostudies-literature