%0 Nanopartikel unedler Metalle (Mg0, Al0, Gd0, Sm0) %A Stadler, Andreas %E Knieps-Grünhagen, Esther %E Bocola, Marco %E Lohstroh, Wiebke %E Zamponi, Michaela %E Krauss, Ulrich %I Cell Press %D 2016 %C Cambridge, Mass. %T Photoactivation Reduces Side-Chain Dynamics of a LOV Photoreceptor %U http://juser.fz-juelich.de/record/283547/files/1-s2.0-S0006349516000977-main.pdf %U http://juser.fz-juelich.de/record/283547/files/1-s2.0-S0006349516000977-main.gif?subformat=icon %U http://juser.fz-juelich.de/record/283547/files/1-s2.0-S0006349516000977-main.jpg?subformat=icon-1440 %U http://juser.fz-juelich.de/record/283547/files/1-s2.0-S0006349516000977-main.jpg?subformat=icon-180 %U http://juser.fz-juelich.de/record/283547/files/1-s2.0-S0006349516000977-main.jpg?subformat=icon-640 %U http://juser.fz-juelich.de/record/283547/files/1-s2.0-S0006349516000977-main.pdf?subformat=pdfa %X We used neutron-scattering experiments to probe the conformational dynamics of the light, oxygen, voltage (LOV) photoreceptor PpSB1-LOV from Pseudomonas putida in both the dark and light states. Global protein diffusion and internal macromolecular dynamics were measured using incoherent neutron time-of-flight and backscattering spectroscopy on the picosecond to nanosecond timescales. Global protein diffusion of PpSB1-LOV is not influenced by photoactivation. Observation-time-dependent global diffusion coefficients were found, which converge on the nanosecond timescale toward diffusion coefficients determined by dynamic light scattering. Mean-square displacements of localized internal motions and effective force constants, , describing the resilience of the proteins were determined on the respective timescales. Photoactivation significantly modifies the flexibility and the resilience of PpSB1-LOV. On the fast, picosecond timescale, small changes in the mean-square displacement and are observed, which are enhanced on the slower, nanosecond timescale. Photoactivation results in a slightly larger resilience of the photoreceptor on the fast, picosecond timescale, whereas in the nanosecond range, a significantly less resilient structure of the light-state protein is observed. For a residue-resolved interpretation of the experimental neutron-scattering data, we analyzed molecular dynamics simulations of the PpSB1-LOV X-ray structure. Based on these data, it is tempting to speculate that light-induced changes in the protein result in altered side-chain mobility mostly for residues on the protruding Jα helix and on the LOV-LOV dimer interface. Our results provide strong experimental evidence that side-chain dynamics play a crucial role in photoactivation and signaling of PpSB1-LOV via modulation of conformational entropy.