Particular „Ice-nucleating proteins“ produced by certain bacteria have the ability to control the freezing point of water – so efficiently that no other known material can compete. An interdisciplinary team led by Konrad Meister from the Max Planck Institute for Polymer Research has now uncovered how these proteins operate and how their activity can be precisely regulated. Their findings show that just a handful of assembled proteins is sufficient to achieve maximum activity—and that these proteins preferentially assemble under specifically induced conditions.