Protein functionality classification for bio-inspired water desalination

Water scarcity is a major global problem, still affecting several countries around the world. Designing and producing efficient systems for water desalination at low cost is then key to ensure better life conditions to millions of people. In this view, the idea to mimic Nature and to take inspiration from some mechanisms in living cells, has recently attracted attention as a promising engineering pathway. In particular, a specific family of proteins, called aquaporins (AQPs), are being studied to create bio-inspired membranes for water purification: in 2021 the company Aquaporin A/S began indeed to produce and to export water purifiers using aquaporins. The aim of this work is to investigate the structural determinants for specific desired properties in proteins, such as high water permeability and salt rejection. Starting from the aquaporins, since they have already proved to possess these properties, a comparative analysis has been carried out, with a specific focus on the 3D structure. Three non-AQPs with some features in common with aquaporins have been found, and they could serve as a starting point for further research. Finally, water permeabilities of the major aquaporins have been collected, in order to have a specific target for a future comparison with the identified non-AQPs potential candidates.