Ultrafast light-induced dynamics in the microsolvated biomolecular indole chromophore with water

Interactions between proteins and their solvent environment can be studied in a bottom-up approach using hydrogen-bonded chromophore-solvent clusters. The ultrafast dynamics following UV-light-induced electronic excitation of the chromophores, potential radiation damage, and their dependence on solvation are important open questions. The microsolvation effect is challenging to study due to the inherent mix of the produced gas-phase aggregates. We use the electrostatic deflector to spatially separate different molecular species in combination with pump-probe velocity-map-imaging experiments. We demonstrate that this powerful experimental approach reveals intimate details of the UV-induced dynamics in the near-UV-absorbing prototypical biomolecular indole-water system. We determine the time-dependent appearance of the different reaction products and disentangle the occurring ultrafast processes. This approach ensures that the reactants are well-known and that detailed characteristics of the specific reaction products are accessible - paving the way for the complete chemical-reactivity experiment. Experimentally following the ultrafast dynamics of microsolvated molecules is challenging due to the inherently produced soup mix of various gas-phase aggregates. Here, the authors exploit neutral-species selection to reveal intimate details of the UV-induced ultrafast dynamics in the prototypical indole-water system.

Automated summary

Protein-solvent interactions can be studied using hydrogen-bonded chromophore-solvent clusters. This study focuses on the ultrafast dynamics following UV-light-induced electronic excitation of the chromophores in a biomolecular system. By using the electrostatic deflector in combination with pump-probe velocity-map-imaging experiments, the authors reveal intimate details of the UV-induced dynamics and determine the time-dependent appearance of different reaction products.