Figure 4: Time-resolved absorption spectroscopy and crystallography on bR crystals. | Nature Communications

Figure 4: Time-resolved absorption spectroscopy and crystallography on bR crystals.

From: Lipidic cubic phase injector is a viable crystal delivery system for time-resolved serial crystallography

Figure 4

Time-resolved absorption spectroscopy on bR crystals (a) indicates similar photocycle kinetics as observed in purple membranes44,58. Absorption changes at 412 nm (b) indicate maximum accumulation of the M intermediate at ∼1 ms after photoexcitation. The TR-SFX Fourier difference map with 1 ms time delay (Fobs(bR1ms)-Fobs(dark_bR); turquoise positive, magenta negative, shades represent 2.0, 2.5 and 3.0 σ) is compatible with known light-induced conformational changes characteristic for the bR M intermediate (dark (purple), M state (pink) and 1CWQ49). Reorganization in the proton transfer chain in the M intermediate involves a rotamer change of Arg82 and relocation of water molecules (c). Difference peaks around the site of retinal attachment Lys216 show a shift of helix G (d). Arrows indicate conformational changes apparent in the difference Fourier analysis.

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