Researchers have uncovered the mechanism that allows spiders to build such strong webs.
One of the world’s strongest materials, spider silk, has baffled scientists for centuries. It’s lightweight, stretchy, stronger than steel, and produced by spiders using water as a solvent, but how do these animals produce this fibre?
It all comes down to silk proteins known as spidroins, which are made of about 3,500 organic compounds known as amino acids. Spiders store spidroins as soluble proteins in their silk glands. But, when they are about to use them to spin their web, the structure of the spidroins changes as it exits the spider's silk gland, becoming solid fibers.
It all comes down to silk proteins known as spidroins, which are made of about 3,500 organic compounds known as amino acids. Spiders store spidroins as soluble proteins in their silk glands. But, when they are about to use them to spin their web, the structure of the spidroins changes as it exits the spider's silk gland, becoming solid fibers.
Scientists from the Swedish University of Agricultural Science and the Karolinska Institute have found that the spindroins reach an acidic pH level of about 5.7 inside the glands when the spider is making its web. They also found a higher concentration of bicarbonate ions inside the gland when the web is being spun.
According to their research, both ends of the spider's silk grand have different pH levels, which helps these proteins become a solid fibre that can be spun into a solid web. They also found that the pH level has different effects on the stability of the two regions at each end of the spindroin proteins. “While one of the ends tended to pair up with other molecules at the beginning of the duct (N-terminal) and became increasingly stable as the acidity increased along the duct, the other end (C-terminal) destabilised as the acidity increased, and gradually unfolded until it formed the structure characteristic of silk at the acidic pH of 5.5”, explained the researchers in a press release.
Published in the journal PLoS Biology, the study suggests a new ‘lock and trigger’ model for spider silk formation, explaining how the material forms so quickly within the spinning duct of the spiders.
According to their research, both ends of the spider's silk grand have different pH levels, which helps these proteins become a solid fibre that can be spun into a solid web. They also found that the pH level has different effects on the stability of the two regions at each end of the spindroin proteins. “While one of the ends tended to pair up with other molecules at the beginning of the duct (N-terminal) and became increasingly stable as the acidity increased along the duct, the other end (C-terminal) destabilised as the acidity increased, and gradually unfolded until it formed the structure characteristic of silk at the acidic pH of 5.5”, explained the researchers in a press release.
Published in the journal PLoS Biology, the study suggests a new ‘lock and trigger’ model for spider silk formation, explaining how the material forms so quickly within the spinning duct of the spiders.
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