Creating Artificial, Tough, Stretchy Spider Silk from Proteins

Spider silk is incredibly tough and slightly stretchy, creating the perfect tool for spiders to capture their prey. Now, though, scientists are looking into harvesting spider silk's mechanical properties to create their own artificial silk.

In this case, the researchers focused on the toughest of the spider's seven types of silk: aciniform silk. This silk is used to wrap up prey that blunders into its web. Over the past few years, researchers have managed to unravel its protein architecture and understand the connection between its structure and function. This could lead to the creation of artificial silk.

The first step in creating this silk is to replicate the proteins that make up the natural version. In this case, the scientists need to recombinantly express them in E. coli. The key protein is ACSp1, which has three parts. Most of the protein is a repeated sequence of about two hundred amino acids. Two tails called the N- and C- terminal domains hang off of each end of the protein chain.

After analyzing the structure of the protein, the next step in creating artificial silk is to spin the proteins into long strands. Spiders have specialized equipment to do so, but finding the precise lab conditions to mimic this process is a huge challenge. Now, though, researchers have found a clue to fiber formation process in the C-terminal domain. It turns out that the region in general helps with fiber formation and that replacing the aciniform silk c-terminal domains with c-terminal domains from other types of spider silk improves fiber formation.

"Now we know that c-terminal domains are interchangeable," said Lingling Xu, one of the researchers, in a news release. "This could be useful when we encounter problems while producing recombinant spidroins."

The findings may just help create artificial spider silk in the future. Currently, scientists are still working on making commercial production feasible and synthesize fibers that mimic the mechanical properties of spider silk.

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