Scientists have identified a novel antifreeze molecule in a freeze-tolerant Alaska beetle able to survive temperatures below minus 100 degrees Fahrenheit. Unlike all previously described biological antifreezes that contain protein, this new molecule, called xylomannan, has little or no protein. It is composed of a sugar and a fatty acid and may exist in new places within the cells of organisms. "The most exciting part of this discovery is that this molecule is a whole new kind of antifreeze that may work in a different location of the cell and in a different way," said Dr. Brian Barnes, director of the University of Alaska Fairbanks Institute of Arctic Biology and one of five scientists who participated in the Alaska Upis ceramboides beetle project. A possible advantage of this novel molecule comes from it having the same fatty acid that cell membranes do. This similarity, said Dr. Barnes, may allow the molecule to become part of a cell membrane and protect the cell from internal ice crystal formation. Antifreeze molecules made of proteins may not fit into cell membranes. This report was featured as one of the cover articles in the December 1 issue of PNAS. [Press release] [PNAS abstract]
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