Dr. Ran Drori, visiting assistant professor in the chemistry and biochemistry departments at Stern College for Women, has co-authored a paper which has been accepted for publication in the Journal of the American Chemical Society. Titled “Antifreeze Glycoproteins Bind Irreversibly to Ice,” the paper explains, according to Dr. Drori, “why and how Antarctic fish don’t freeze to death.”

Fish living in very cold waters produce antifreeze glycoproteins through their pancreas, esophagus and stomach. These proteins bind onto ice crystals in the fishes’ blood and prevent the crystals from growing, which is crucial for the fishes’ survival because large crystals can tear living cells to shreds. Some fish, like the naked dragon fish, cover themselves with antifreeze slime to prevent ice crystals from rupturing their skin.

Past research has assumed an irreversible binding of the proteins to embryonic ice crystals and the inhibition of further growth. However, the binding process is poorly understood, and Dr. Drori and his co-authors examined if these proteins stay bound to the ice until it melts or if they are released from the ice surface.

Using a dye and microfluidics techniques, Dr. Drori and his co-authors demonstrated that antifreeze glycoproteins bind irreversibly to ice regardless of the crystals’ sizes.

Understanding how antifreeze glycoproteins inhibit ice will facilitate their use in many fields that require controlling ice growth, including preventing frost injury in agriculture, developing new food products and preserving organs at low temperatures.

“When I was a graduate student,” Drori said, “I showed that antifreeze proteins from fish and insects bind irreversibly to ice, which is unusual for most biological molecules. In my recent work with colleagues from the Netherlands and the University of Illinois, we were able to use a unique approach to demonstrate that all types of antifreeze glycoproteins from Antarctic fish bind irreversibly to ice. In the future, we plan to reveal further insights into the interaction of biological molecules and cells with ice crystals.”

Other articles by Dr. Drori on this topic include “Scientists log newfound understanding of water’s responses to changing temperatures” and “Supramolecules break the ice.”

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