Mutation studies reveal how Antarctic octopus arms itself with cool enzyme

A handful of amino acid mutations in an enzyme from an Antarctic octopus arms it with remarkable cold tolerance. The discovery came from comparing enzymes from a cold-water and a temperate-water species. Insight into the cold-adapted enzyme might have relevance for cryogenic preservation or organ transplantation.

Researchers in the US began by investigating the workings of a crucial Na+/K+ pump from an octopus that had been collected below the ice in McMurdo Station, Antarctica. This Na+/K+ ion pump, powered by ATP, pushes three sodium ions out for every two potassium ions in, generating the electrochemical gradient that is critical to allow neurons to fire. In neurons, the activity of this protein uses around three-quarters of a cell’s total energy output, notes lIya Levental, a molecular physiologist at the University of Virginia.