MS23-P12 Experimental and computational reduction of dynamical electron scattering allows visualizing individual hydrogen atomsElectron crystallography allows structure solution of beam-sensitive organic pharmaceuticals and macromolecules when only nanometre-sized crystals are available. Compared to X-rays, electron diffraction faces a crucial challenge: dynamical electron scattering compromises structure solution and its effects can only be modelled in specific cases. Dynamical scattering can be reduced experimentally by decreasing crystal size – but not without a penalty, as it also reduces the overall diffracting intensity. To boost the very weak diffraction data, the crystals were cryo-cooled and we employed a fast and highly sensitive hybrid pixel detector. Here we show that nanometre-sized crystals from organic pharmaceuticals allow visualization and unconstrained positional refinement of the hydrogen atoms, even whilst ignoring the effects of dynamical scattering during refinement. Furthermore, we introduce a general likelihood-based computational approach for further reducing the adverse effects of dynamic scattering, which significantly improved model accuracy – even for protein crystal data at substantially lower resolution.
Keywords: electron diffraction, hydrogen atoms, dynamical scattering