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Resumen:
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Antifreeze proteins (AFPs) are biopolymers capable of interfering with ice growth. Their antifreeze action is commonly understood considering that the AFPs, by pinning the ice surface, force the crystal–liquid interface to bend forming an ice meniscus, causing an increase in the surface free energy and resulting in a decrease in the freezing point ?T max. Here, we present an extensive computational study for a model protein adsorbed on a TIP4P/Ice crystal, computing ?T max as a function of the average distance d between AFPs, with simulations spanning over 1 ?s. First, we show that the lower the d, the larger the ?T max. Then, we find that the water–ice–protein contact angle along the line ?T max(d) is always larger than 0? , and we provide a theoretical interpretation. We compute the curvature radius of the stable solid–liquid interface at a given supercooling ?T ? ?T max, connecting it with the critical ice nucleus at ?T. Finally, we discuss the antifreeze capability of AFPs in terms of the protein–water and protein–ice interactions. Our findings establish a unified description of the AFPs in the contest of homogeneous ice nucleation, elucidating key aspects of the antifreeze mechanisms and paving the way for the design of novel ice-controlling materials.
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