Different paths, same purpose: How antifreeze proteins stop ice crystals from growing

To survive in freezing environments, different organisms have evolved a remarkable class of proteins, known as antifreeze proteins (AFPs), which inhibit the growth of internal ice crystals. Due to their ability to function at trace concentrations, AFPs are being explored for wide-ranging applications, from cryopreservation to food storage. However, AFP structure-activity relationships are incredibly complex and remain poorly understood, constituting a bottleneck in our efforts to translate the vast untapped potential of these evolutionary marvels. Complicating things further, AFPs derived from insects and fish perform the exact same function-inhibiting ice growth-using two fundamentally different mechanisms. This mechanistic dichotomy results in different failure modes and, correspondingly, in different structure-function relationships. This perspective seeks to shed light on how different AFPs use different mechanisms to achieve the same objective while highlighting gaps that remain in our understanding of how AFPs function.