[24] Electron spin labels

摘要: Publisher Summary This chapter discusses the molecular structure of spin labels. The also basic components nitroxide electron paramagnetic resonance (EPR) spectrum, Hamiltonian, and factors that influence spectrum. Most commonly, labels are used to probe motion, so following section is devoted tumbling correspondence time scales spectra. conventional EPR spectrum along diagonal, off-diagonal cross-peaks provide evidence exchange among hyperfine lines. cross-peak outermost lines provides direct Heisenberg (HSE). HSE was determined with time-consuming variable-concentration experiments, but two-dimensional (2D) spectroscopy can quickly determine rate at just a single concentration. Such 2D techniques may prove be very useful in study recognition other biological processes rely on encounters biomolecules.