Structure and dynamics of spin label side chains in KvAP voltage-sensor domain: an all-atom MD simulation study

Site-directed spin labeling (SDSL) combined with continuous-wave electron paramagnetic resonance (CW-EPR) spectroscopy has become a useful approach to investigate the structural and dynamical properties of biomolecules, especially membrane protein. In this method, spin label side chains due to their motion highly depending on the local environment were employed as external molecules to probe the structure and dynamics of the membrane protein. The close relationships between the dynamics of the spin label side chain and protein structure have been studied for T4 lysozyme. Besides, molecular dynamics (MD) simulations were widely applied as a powerful tool to study the microscopic behavior of the proteins, completing experimental approaches. Here, we presented an all-atom MD simulation study of the nitroxide spin label (MTSSL) in the X-ray structure of a potassium channel voltage-sensor domain (VSD) from Aeropyrum Pernix (KvAP).