Small-angle X-ray scattering study of the kinetics of light-dark transition in a LOV protein.
Rollen, K., Granzin, J., Batra-Safferling, R., Stadler, A.M.(2018) PLoS One 13: e0200746-e0200746
- PubMed: 30011332 
- DOI: https://doi.org/10.1371/journal.pone.0200746
- Primary Citation of Related Structures:  
6GG9 - PubMed Abstract: 
Light, oxygen, voltage (LOV) photoreceptors consist of conserved photo-responsive domains in bacteria, archaea, plants and fungi, and detect blue-light via a flavin cofactor. We investigated the blue-light induced conformational transition of the dimeric photoreceptor PpSB1-LOV-R66I from Pseudomonas putida in solution by using small-angle X-ray scattering (SAXS). SAXS experiments of the fully populated light- and dark-states under steady-state conditions revealed significant structural differences between the two states that are in agreement with the known structures determined by crystallography. We followed the transition from the light- to the dark-state by using SAXS measurements in real-time. A two-state model based on the light- and dark-state conformations could describe the measured time-course SAXS data with a relaxation time τREC of ~ 34 to 35 min being larger than the recovery time found with UV/vis spectroscopy. Unlike the flavin chromophore-based UV/vis method that is sensitive to the local chromophore environment in flavoproteins, SAXS-based assay depends on protein conformational changes and provides with an alternative to measure the recovery kinetics.
Organizational Affiliation: 
Institute of Complex Systems, ICS-6: Structural Biochemistry, Forschungszentrum Jülich, Jülich, Germany.