Heat-stable antifreeze protein from grass.

We have discovered an antifreeze protein1 in an overwintering perennial ryegrass, Lolium perenne. The protein is stable at 100 °C and although it is a less effective antifreeze than proteins found in antarctic fish and insects, it is better at preventing ice recrystallization. This property enables grasses to tolerate ice formation in their tissues without being damaged, suggesting that the control of ice-crystal growth rather than the prevention of freezing may have evolved to be the critical factor in their survival at very low temperatures.