0000000000135230
AUTHOR
Irina Kosheleva
Visualizing a protein quake with time-resolved X-ray scattering at a free-electron laser
We describe a method to measure ultrafast protein structural changes using time-resolved wide-angle X-ray scattering at an X-ray free-electron laser. We demonstrated this approach using multiphoton excitation of the Blastochloris viridis photosynthetic reaction center, observing an ultrafast global conformational change that arises within picoseconds and precedes the propagation of heat through the protein. This provides direct structural evidence for a 'protein quake': the hypothesis that proteins rapidly dissipate energy through quake-like structural motions. peerReviewed
Structural photoactivation of a full-length bacterial phytochrome
Time-resolved x-ray solution scattering reveals the conformational signaling mechanism of a bacterial phytochrome.
Photoactivation of Drosophila melanogaster cryptochrome through sequential conformational transitions
Time-resolved x-ray scattering reveals light-induced signal transduction in insect cryptochromes.
Signal amplification and transduction in phytochrome photosensors
[Introduction] Page 2 of 20 Sensory proteins must relay structural signals from the sensory site over large distances to regulatory output domains. Phytochromes are a major family of red-light sensing kinases that control diverse cell ular functions in plants, bacteria, and fungi. 1-9 Bacterial phytochro mes consist of a photosensory core and a C-te rminal regulatory domain. 10,11 Structures of photosensory cores are reported in the resting state 12-18 and conformational responses to light activat ion have been proposed in the vicinity of the chromophore. 19-23 However, the structure of the signalling state and the mechanism of downstream signal re lay through the photosensory core remain e…
Sequential conformational transitions and α-helical supercoiling regulate a sensor histidine kinase
Sensor histidine kinases are central to sensing in bacteria and in plants. They usually contain sensor, linker, and kinase modules and the structure of many of these components is known. However, it is unclear how the kinase module is structurally regulated. Here, we use nano- to millisecond time-resolved X-ray scattering to visualize the solution structural changes that occur when the light-sensitive model histidine kinase YF1 is activated by blue light. We find that the coiled coil linker and the attached histidine kinase domains undergo a left handed rotation within microseconds. In a much slower second step, the kinase domains rearrange internally. This structural mechanism presents a t…
Room temperature crystal structure of the fast switching M159T mutant of the fluorescent protein dronpa
The fluorescent protein Dronpa undergoes reversible photoswitching reactions between the bright ‘on’ and dark ‘off’ states via photoisomerisation and proton transfer reactions. We report the room temperature crystal structure of the fast switching Met159Thr mutant of Dronpa at 2.0 A resolution in the bright on state. Structural differences with the wild type include shifted backbone positions of strand β8 containing Thr159 as well as an altered A-C dimer interface involving strands β7, β8, β10, and β11. The Met159Thr mutation increases the cavity volume for the p-hydroxybenzylidene-imidazolinone chromophore as a result of both the side chain difference and the backbone positional difference…