Submillisecond Freezing Permits Cryoprotectant-Free EPR Double Electron-Electron Resonance Spectroscopy.

ABSTRACT: Double electron-electron resonance (DEER) EPR spectroscopy is a powerful method for obtaining distance distributions between pairs of engineered nitroxide spin-labels in proteins and other biological macromolecules. These measurements require the use of cryogenic temperatures (77 K or less) to prolong the phase memory relaxation time (T_m ) sufficiently to enable detection of a DEER echo curve. Generally, a cryoprotectant such as glycerol is added to protein samples to facilitate glass formation and avoid protein clustering (which can result in a large decrease in T_m ) during relatively slow flash freezing in liquid N₂ . However, cryoprotectants are osmolytes and can influence protein folding/unfolding equilibria, as well as species populations in weak multi

SUBMITTER: Schmidt T 

PROVIDER: S-EPMC8179457 | biostudies-literature | 2020 Jun

REPOSITORIES: biostudies-literature