Figure 2. Ice nucleation activity of mutant INPs in which R-coils are incrementally replaced with WO-coils.

A) Diagram indicating the domain map of PbINP and from it, the design of the INP mutants. Sections of the WO-coils used in the replacement of the R-coils are indicated. wt: wild type. B) Ice nucleation temperatures measured by WISDOM for E. coli cells expressing PbINP and mutants with different numbers of R-coils. The temperature at which fifty percent of the droplets froze (T₅₀) is indicated with a hollow circle, and its corresponding value written nearby. The shaded region indicates standard deviation. C) The same constructs assayed for ice nucleation using a nanoliter osmometer. The grey box indicates temperatures beyond the lower limit of the NLO apparatus for detecting ice nucleation in this experiment.