Screening and Activity Evaluation of Peptides With Anti‐Ice‐Nucleation Activity Using the Phage Display Library Method

We screened for anti‐ice‐nucleation peptides using the phage display library method, with silver iodide as the target for artificial ice nucleation The phage interacted with the silver iodide in a dispersed state, rather than in an immobilized state. Based on DNA analysis, we identified five peptides with high expression levels. Five peptide sequences were synthesized by hand using the Fmoc solid‐phase peptide synthesis and evaluated their anti‐ice‐nucleation activity. Three peptide sequences exhibited anti‐ice‐nucleation activity, and two of them were insoluble in water. Among the three peptides, SHIARSV exhibited the highest anti‐ice‐nucleation activity. To determine the importance of each amino acid in SHIARSV, we designed five peptides in which Ala was substituted and examined their anti‐ice‐nucleation activity. As a result, we identified AHIARSV, a peptide sequence with higher anti‐ice‐nucleation activity than the original SHIARSV sequence. This peptide exhibited high levels of both anti‐nucleation activity and ice recrystallization inhibition activity. It is our conclusion that the design of antifreeze peptides with activities comparable with those of natural ones is highly feasible.