Polyol-Induced 100-Fold Enhancement of Bacterial Ice Nucleation Efficiency.

Ice-nucleating proteins (INPs) from bacteria like Pseudomonas syringae are among the most effective ice nucleators known. However, large INP aggregates with maximum ice nucleation activity (at approximately -2 °C) typically account for less than 1% of the overall ice nucleation activity in bacterial samples. This study demonstrates that polyols significantly enhance the assembly of INPs into large aggregates, dramatically improving bacterial ice nucleation efficiency. Simple compounds like polyvinyl alcohol increased the abundance of large INP aggregates by a factor of 100. This remarkable boost in ice nucleation efficiency is attributed to the stabilization of INP aggregates through membrane-polyol interactions that stabilize INP interactions and reduce structural fluctuations. The ability to regulate the abundance of large INP aggregates in bacterial ice nucleators enables fine-tuning ice nucleation processes at much lower concentrations for specific biomedical and technological purposes.