Regensburg 2019 – scientific programme

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BP: Fachverband Biologische Physik

BP 9: Computational biophysics

BP 9.1: Invited Talk

Tuesday, April 2, 2019, 09:30–10:00, H11

Biomolecular structure determination from single molecule X-ray scattering with three photons per image — •Helmut Grubmueller and Benjamin von Ardenne — Department of Theoretical and Computational Biophysics, Max Planck Institute for Biophysical Chemistry, Am Fassberg 11, 37077 Göttingen, Germany

Scattering experiments with femtosecond high-intensity free-electron laser pulses provide a new route to time resolved macromolecular structure determination. While currently limited to nano-crystals or virus particles, the ultimate goal is scattering on single biomolecules. The main challenge in these experiments is the extremely low signal-to-noise ratio due to the very low expected photon count per scattering image, often well below 100. We describe a correlation-based approach and show that three coherently scattered photons per image suffice for structure determination. Using synthetic scattering data of a small protein, we demonstrate near-atomic resolution of 3.3 A using 3.3 × 10¹⁰ coherently scattered photons from 3.3 × 10⁹ images, which is within experimental reach. Our correlation approach is robust to additional noise from incoherent scattering.