"Sometimes proteins are like the Wicked Witch. Add water, wait a nanosecond and you can almost hear that piteous whimper. "I'm mel-l-l-ting!" Well, not really. But there may be an audible groan from biochemists as they observe simulations of a large protein or DNA in water. For a few hundred picoseconds of simulation time it looks fine, then the molecule appears to unravel. It's been a troubling problem, but with a series of computations at the Pittsburgh Supercomputing Center, Tom Darden and Lee Pedersen seem to have it fixed. "