Wyoming Researchers Discover High-Performance Spider Silk Genes

Randy Lewis, professor, and Cheryl Hayashi, post doctoral researcher, in the UW College of Agriculture's Department of Molecular Biology, report the discovery of a new spider silk gene that codes for a flagelliform (long, whip-like) silk protein. Their discovery will be published this month in the Journal of Molecular Biology.

Silk produced from the newly-discovered gene is used as the core thread of an orb web's capture spiral and is the most highly elastic of spider silks, Lewis says. This elasticity is essential for prey capture by allowing the web to absorb the energy of a flying insect, entrapping it in the web. Lewis says the discovery, "helps unlock more of the spiders' secrets for spinning high-performance fibers."

This discovery is essential to the ongoing spider silk research at UW, Lewis says, which has included cloning the DNA of spider silk that can be used for a variety of industrial and medicinal uses. UW researchers were the first to clone proteins that comprise major ampullate silk, but little was known about the flagelliform silk protein until now.

Lewis and Hayashi's discovery of the new gene has revealed more than just the DNA or amino acid sequences of the flagelliform silk protein. The gene provides the first depiction of the amino-terminal (start of the protein) protein of a spider silk.

"This region is widely thought to be involved in the transport of newly synthesized proteins out of secretory cells," Lewis says. "This provides an additional clue to understanding how spiders are able to manufacture, store and then spin silk fibers -- processes that are currently under intense study by several laboratories across the country."

But what Lewis and Hayashi have discovered is that flagelliform silk protein is made of numerous copies of three distinct amino acid motifs.

"Spider silks can be envisioned as sets of amino acid motifs with each motif forming a different structure," Hayashi says. Flagelliform silk is built largely of the elastic-conferring module, she says. "It is not only the presence, but also the frequency of these modules that contributes to the properties of each silk. While flagelliform has at least 43 uninterrupted modules, dragline silk has at most nine consecutive units. The greater extensibility of the capture spiral can be attributed to its greater proportion of spring-like elastic modules." Lewis and Hayashi's research work is funded with a grant from the Army Research Office, and is the basis for a Small Business Innovative Research (SBIR) grant awarded to WyoBiGen, a company formed to commercialize research discoveries from Lewis' UW laboratory. WyoBiGen is a Laramie company created to commercialize artificial spider silks.

"The world-wide market for these fibers is likely to be in the hundreds of millions of dollars," Lewis says.

The SBIR program encourages small businesses to apply for funds that have been set aside for the critical start-up and development stages. The SBIR encourages the commercialization of technologies, products, or services, which, in turn, stimulate the U.S. economy. UW's Office of Research has hired Chris Busch, an expert in SBIR proposals, to work with small businesses in Wyoming.