New Scientist
Image: derekkeats
To survive in frigid polar regions, many cold-blooded creatures employ a natural antifreeze to protect themselves from the damage that large ice crystals would cause. These antifreeze molecules lock onto ice crystals, but not liquid water – though how they do this has been a mystery.
Now the mechanism has been revealed, opening the way to using similar molecules in cancer treatments, to protect healthy tissue while tumours are destroyed by freezing.
Antifreeze proteins (AFPs) found in nature lock onto ice crystals and stop them growing large enough to damage tissue. If AFPs bound as easily to liquid water as they do to ice, this lifesaving action could turn killer, as animals would quickly dehydrate, says Matthew Blakeley at the Laue-Langevin Institute in Grenoble, France.
X-ray diffraction has already helped to show that the surface of the AFPs that binds to ice is covered in tiny hydrophobic spikes. Now, using neutron diffraction, which is more effective at showing up the hydrogen in water molecules, Blakeley and colleagues managed to catch four water molecules at the ice-binding surface of AFPs from a fish, the ocean pout (Zoarces americanus). The water molecules formed an arc resembling part of a six-molecule ring characteristic of ice crystals. At the centre of each ring is a nanoscale hole. Read more on newscientist.com…
