Nearly two decades after the discovery of knotted proteins, most researchers think the strangely tangled molecules are too unwieldy to play much part in a cell's activities. This notion is changing.

Many of the processes essential to life involve proteins -- long molecules which 'fold' into three-dimensional shapes allowing them to perform their biological role. Many of the processes essential to ...

Tie a trefoil knot in a piece of string, seal the ends together, and try to wiggle it free without cutting. In three-dimensional space, the knot holds firm. Add a fourth spatial dimension, however, ...