The springy molecule that gives fleas their amazing jumping ability has been mimicked in the laboratory. The material could one day be used in anything from bouncy balls to spinal implants, hope scientists.
Resilin is a rubbery protein that is found in a range of insects. As well as storing elastic energy in fleas, it helps flying insects’ wings to flex without causing damage to the tissue that connects wing and body.
“Resilin is much more resilient than any other rubber around,” explains Chris Elvin, a biochemist at CSIRO Livestock Industries in St Lucia, Australia, who led the team that created the synthetic resilin. This resilience means that it can be stretched over and over again without losing its elastic properties.
To make the synthetic resilin, Elvin and his team isolated a portion of the resilin gene from the fruitfly Drosophila melanogaster, and inserted it into Escherichia coli bacteria. A brew of the microbes generated several grams of the protein pro-resilin, which is a precursor to resilin itself.
The researchers then mixed pro-resilin with a ruthenium catalyst under a light, which knitted together units of the amino acid tyrosine within the molecules. After just 20 seconds the liquid mixture turned into a rubbery solid that behaved exactly like resilin itself, they report in this week’s Nature1.
The reaction worked on the very first attempt, recalls Elvin. “I remember running around the lab that day showing it to everybody, saying ‘Here, feel this!’,” he laughs.
Although the gene that generates resilin in fruitflies had already been tentatively identified by other researchers2, the precise code for making resilin was not known. So the Australian scientists picked out a small section of DNA at the end of the gene that contained lots of repeating sections of code, hoping that it would make resilin.
They reasoned that as elastic proteins in nature are often made of repeating sequences of amino acids, the genes responsible for constructing them must also be repetitive. “It was a bit of a guess,” admits Elvin.
By Mark Peplow