Ice-Binding Proteins

Ice-binding proteins (IBPs) are proteins that depress the freezing point but not the melting point of aqueous solutions by inhibiting the growth of ice crystals. The difference between the freezing and melting points is called thermal hysteresis (TH).  In addition, many IBPs show ice-recrystallization (IR) inhibition property. IR is a major cause of cell damage by freezing. As the name implies, IBPs are a broad term describing any protein that binds to ice. IBPs include antifreeze proteins (AFPs), proteins that inhibit ice recrystallization (IRIPs), proteins that anchor something to ice, and possibly even ice nucleation proteins (INPs). However, AFP is somewhat a misnomer because this type of protein does not prevent freezing. Hence, in some of the literature, AFPs have been termed TH proteins (THPs), according to their activity, or ice structuring proteins (ISPs), since they control the shape and size of ice crystals. Conventionally, in much of the literature, IBP and AFP are interchangeable because further investigation has revealed that, in most cases, IBPs possess TH activity. The intriguing properties of IBPs have drawn interest from academia and industries because these proteins have broad potential applications, including cryopreservation, food preservation, transgenic technology, and cryosurgery (Davies, P.L. et al. 1989; Hew, C.L. et al. 1992; Wohrmann, A. 1996; Barrett, J. 2001; Ben, R.N. 2001; Bouvet, V. & Ben, R.N. 2003; Harding, M.M. et al. 2003; Fuller, B.J. 2004).  In my lab, we are interested in finding and characterizing new IBPs, designing new artificial IBPs using AI algorithms, and developing new cryoprotectants based on IBPs.