Transient Complex Formation in Nanodroplets (360G-Wellcome-204732_Z_16_Z)

Networks of molecular complexes play a fundamental role in biology. Transient interactions often regulate these networks and thus targeted interference offers possibilities for therapeutical intervention. Capturing these elusive complexes is far from trivial. Many are only present at low concentrations because of low-affinity, low solubility or high toxicity. Only a few have been captured and characterised. The physical chemistry of nanodroplets offers a way to enhance the formation of such biological complexes. Droplet populations can be created containing copies of different molecules and combinations of molecules in a statistical distribution. Controlled shrinkage of the droplets by evaporation slowly increases the effective concentration and drives energetically favoured interactions between trapped molecules. The complexes can then be structurally characterised by mass spectrometry, electron microscopy, and flash imaging with X-ray free-electron lasers. I plan to study two complexes: the poorly understood Rubisco - Rubisco-activase complex at the centre of plant carbon fixation, and the FANC core complex, where mutations cause DNA repair malfunctions, resulting in cytopenia, developmental defects, and tumor predisposition. The nanodroplet technology I will develop will make such hitherto difficult to study transient complexes of medical and biotechnological importance accessible to structural analysis.