DEER Distance Measurement Between a Spin Label and a Native FAD Semiquinone in Electron Transfer Flavoprotein

摘要

Protein structures are commonly determined by X-ray crystallography and NMR spectroscopy, but there are drawbacks to these methods. For example, some proteins can be crystallized, but there are examples in which crystallization conditions generate nonbio-logically relevant conformations.A complementary method of obtaining structural information for proteins without growing crystals is site-directed spin labeling (SDSL) and pulsed electron paramagnetic resonance (EPR) spectroscopy.Double electron-electron resonance (DEER) experiments can provide information on the distribution of distances between two paramagnetic sites in macromolecules (including nucleic acids) and has proven to be an effective way to study the conformational changes induced by protein-protein interactions.