TY  - JOUR
AU  - Stadler, Andreas
AU  - Knieps-Grünhagen, Esther
AU  - Bocola, Marco
AU  - Lohstroh, Wiebke
AU  - Zamponi, Michaela
AU  - Krauss, Ulrich
TI  - Photoactivation Reduces Side-Chain Dynamics of a LOV Photoreceptor
JO  - Biophysical journal
VL  - 110
IS  - 5
SN  - 0006-3495
CY  - Cambridge, Mass.
PB  - Cell Press
M1  - FZJ-2016-01863
SP  - 1064 - 1074
PY  - 2016
AB  - 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, <k′>, 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 <k′> 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.
LB  - PUB:(DE-HGF)16
UR  - <Go to ISI:>//WOS:000371850000015
C6  - pmid:26958884
DO  - DOI:10.1016/j.bpj.2016.01.021
UR  - https://juser.fz-juelich.de/record/283547
ER  -