Figure 4
Difference electron density maps at a time delay Δt of 256 ns at (a) 293 K and (b) 303 K. Contour levels: −3σ/−4σ (red/white); +3σ/+4σ/+5σ (blue/dark-blue/cyan). The atomic model displayed is that of the reference (dark) state (PDB 2phy
structure) with the HC4-chromophore in its trans configuration. The electron density feature α shows the flip of the carbonyl oxygen of the HC4 tail and β shows the trans to cis isomerization about the double bond, while γ indicates the displacement of the Cys69 sulfur to which the chromophore is bound. |