Abstract:
Heterogeneous ice formation driven by proteins plays a critical role in cryobiology, organismal adaptation, and environmental ice processes. Despite their significance, the molecular mechanisms underlying this activity remain poorly defined. In this presentation, I will discuss our recent work on the structural and physicochemical principles that govern protein-mediated ice nucleation, with a focus on bacterial and fungal ice-nucleating proteins (INPs). Additional comparisons with antifreeze proteins and non-ice-binding proteins help to contextualize key structural features. I will also describe the identification and characterization of a novel class of INPs derived from Mortierella alpina. These proteins show strong nucleation activity, remarkable thermal and pH stability, and operate independently of lipid membranes. Structural analysis reveals a conserved β-solenoid architecture with repetitive ice-binding motifs and terminal disulfide bonds that likely contribute to structural integrity and functional activity. The talk will highlight emerging principles shared across ice-binding proteins, explore how functional protein aggregation modulates ice–protein interactions, and introduce a framework for identifying and investigating new INPs.