Mutational Studies on Antifreeze Proteins

Abstract

When investigating proteins, the possibility of introducing targeted changes and observing their effect can be a useful tool. In regard to antifreeze proteins, this possibility has given rise to various kinds of studies. The method of observing which specific planes on the ice crystal the different antifreeze proteins bind to has been improved by fusing antifreeze proteins to fluorescent proteins. It has also provided insight into whether the antifreeze proteins bind to ice irreversibly or not, by microfluidic experiments. Using site-directed mutagenesis it has been studied how different amino acid side chains, and more specifically their functional groups, affect the interaction with ice. These studies led to a change in the perception that hydrogen bonds were the key force driving the interaction, to believing that the hydrophobic or van der Waals forces are dominant in this regard. It has also been achieved to increase the activity of antifreeze proteins, and though much is still to be learned about the antifreeze proteins, the future mutagenic studies could very well be focusing on optimising the proteins. This could be relevant, not only in regard to activity, but also in the general tailoring of the protein to specific purposes, in order to make the protein relevant for specific commercial respects in the future.