Researchers have tied strings of molecules into a complicated knot whose strands cross one another nine times — an unprecedented feat.
In nature, a DNA molecule often takes the form of one large knot composed of smaller knots. But in the lab, such ‘composite knots’ are difficult to produce in a specific configuration.
To create a composite knot, David Leigh and his colleagues at the University of Manchester, UK, used six iron atoms as scaffolding. Around those atoms, the researchers wove six molecular strands that, between them, contained 324 atoms. The team carefully designed the strands to control their connections with the iron atoms.