FIGURE 2.

(A) Ice crystal planes adsorbed by IBPs. Plant IBPs have demonstrated affinity for primary and secondary prism planes, as well as basal planes. No plant IBPs have yet been identified with pyramidal plane affinity. LpAFP, for example, binds both primary prism and basal planes. (B) Ice crystal morphologies in the absence (a) and presence of an IBP from two grasses (b–h). Lolium perenne LpAFP (1 mg/mL) ice crystal shaping with the a-axes facing toward the reader is shown in B, and with the c-axis toward the reader in c. Shaping in the presence of low concentrations of IBP from Brachypodium distachyon (0.01 mg/mL) is shown in d. Panels (e–h) show an ice crystal burst as the equilibrium freezing point is exceeded. (C) Ice crystal growth following a 24 h annealing period at -6°C demonstrating ice recrystallization inhibition (IRI) by IBPs. Buffer without IBPs (–IBP) contains 100 mM Tris-HCl and 50 mM NaCl. Samples with L. perenne IBP (LpAFP) (+IBP) were diluted to 0.5 mg/mL in the same buffer.