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THE secret of deep-sea living is a molecule that helps proteins keep their
shape under the crushing pressures of the depths, marine biologists have found.
The same chemical may be able to salvage proteins damaged in diseases such as
cystic fibrosis.

Deep-sea creatures endure pressures several hundred times greater than that
at the surface. The high pressures can prevent proteins from folding up to form
working enzymes, according to Paul Yancey of Whitman College in Walla Walla,
Washington. Unfolded proteins are covered with water molecules, but for the
protein molecule to fold up properly this water has to leave. 鈥淗igh pressure
tends to trap water molecules on proteins,鈥� he says.

Yancey has found that deep-sea animals鈥攆rom fish to shrimp and
anemones鈥攃ontain much more of a compound called trimethylamine oxide
(TMAO) than their shallow-living relatives. Furthermore, the higher the pressure
where an animal lives, the greater the concentration of TMAO in its tissues.

Yancey teamed up with Joseph Siebenaller of Louisiana State University in
Baton Rouge to find out if TMAO helps keep the animals鈥� proteins in working
order. They took the same enzyme from three species of scorpion fish living at
different depths, and from a cow. Regardless of the source of the enzyme, adding
TMAO increased the enzyme鈥檚 ability to withstand high pressures and attack by
another enzyme that breaks down proteins.

As TMAO seems ubiquitous among deep-sea animals, it may be a good example of
how different species home in on the same survival trick as they evolve. But its
ability to stabilise a cow enzyme suggests that TMAO鈥檚 protective power extends
much further. In test-tube experiments, William Welch and Christopher Brown of
the University of California at San Francisco have used TMAO to rescue misfolded
proteins produced in cystic fibrosis.

鈥淓ven though humans don鈥檛 have TMAO, it seems to be a universal stabiliser,鈥�
says Yancey. 鈥淭he idea is that it could be used medically also to work on all
sorts of proteins.鈥�