CW-EPR Spectral Simulations: Slow-Motion Regime.

This chapter reviews the range of methods currently available for calculating the electron paramagnetic resonance (EPR) spectrum of nitroxide spin-labeled biomolecules undergoing slow motion. The two major approaches include the stochastic Liouville equation (SLE) which represents the spin label motion using diffusion operators, and the dynamic trajectory (DT) approach, which enables the EPR spectrum to be calculated from molecular dynamics simulations. The basic model parameters needed for each approach are described, together with a broad outline of the theoretical approaches underlying the methods, sufficient to allow their comparison for different applications. Hybrid methods utilizing a combination of SLE and DT approaches are briefly discussed.