For molecular biologist Christopher Elvin, the paper on page 999 of this issue represents the culmination of a lengthy struggle with the insect protein resilin.

This rubber-like molecule first captured his imagination some ten years ago, when he stumbled across a paper from the early 1960s, which detailed the protein's near-100% resilience. “It fascinated me,” says Elvin, who is based at CSIRO Livestock Industries in St Lucia, Australia. “I wanted to know how it worked. What was the mechanism?”

But it wasn't until 2001, when another team of researchers identified the likely gene for resilin in fruitflies, that Elvin was able to launch his project to clone the gene in the bacterium Escherichia coli and so produce the rubbery material.

He and his team found that the resulting recombinant protein could form a material with a variety of sizes and shapes, and that resilin did indeed live up to its name — bouncing back better than today's synthetic rubbers.

Elvin's first brush with resilin came while he was involved in a completely unrelated project. A decade ago, he was working on parasite vaccines for cattle. While looking through the insect literature, he stumbled across a paper by a Danish researcher who had studied the flight of desert locusts and dragonflies. In it, the researcher had documented the extraordinary elastic properties of resilin, which is found in insect joints and tendons, and enables, for example, insects to flap their wings so frequently. Elvin realized that resilin could provide clues about the molecular mechanism of elasticity. But to produce enough of it for experiments, he needed to know which gene was responsible for it.

Although the initial identification of the fruitfly gene for resilin was only tentative, Elvin was convinced by the data that the gene was the one. In 2002, he began a side project to clone the gene into E. coli.

At first things went well — he managed to purify the protein from E. coli and he had it in a soluble form. But then he ran into a serious problem: he couldn't turn the resilin into a useable solid. For a year, he and his team tried various methods of crosslinking the protein molecules so that they would form a rubbery material. One after the other, they failed. “It was very stressful,” says Elvin.

Fortunately, Elvin came across another key paper, published in 1999, that detailed a simple method for making the specific type of crosslink he needed. All he had to do was mix the resilin solution with a heavy-metal complex and a solution of ammonium persulphate in glass moulds and shine white light on them. Ten to twenty seconds later, he got a solid. He was elated. “I was jumping around,” says Elvin.

The researchers are now working on synthetic versions of resilin. They are tweaking the protein's sequence and structure to see what kind of properties and materials they get. For example, they hope to make the rubber stiffer and more biocompatible. Elvin says that the material should one day find a use in medical implants and other devices.