The famous Arrhenius relationship states that things happen faster as they got hotter. In chemistry, that’s generally true but there’s an important exception: the speed at which proteins fold into their functional shape.
It’s easy to think that proteins ought to fold more quickly as they cool down and then unfold more quickly as they heat up. But the actual relationship is both nonlinear and asymmetric, meaning that unfolding is not the reverse of folding.
Molecular biologists have put forward various mechanisms to explain this, such as the nonlinear interaction between water and hydrophobic parts of proteins. But none of these are very convincing.
That looks set to change with the work of Liaofu Luo at the Inner Mongolia University and Jun Lu at the Inner Mongolia University of Technology, both in China. They say that the way folding depends on temperature all becomes clear as soon as you take quantum mechanics into account.
First, a little background on protein folding …