How spiders lock and load to spin their silk
New research published in PLOS Biology aims to help us understand some of the mystery behind our silk-spinning friends.
Scientists are already familiar with the precise site at which spiders form their various types of silk. However, details of spider silk production beyond that have been more elusive—until now.
In order to make spider silk, silk proteins known as spidroins must change from dissolved proteins to solid fibres, and the transformation has to happen at high speed as the spider dances from branch to branch spinning its web. These changes occur as the spidroins travel from one end of a silk gland to the other end, where we get silk in the spider’s spinning duct - but how the transformation took place was unknown.
The researchers have proposed the idea of a “lock and trigger” model for silk formation. They discovered a steep acidity gradient within the silk gland, which causes dramatic structural changes to the ends of each spidroin. These ends first “lock” neighbouring spridoins together to form networks, then triggers these networks to rapidly polymerise into long fibres.
This mechanism helps us understand how spiders form silk so rapidly and effortlessly, and it could one day help us produce biomimetic spidroin fibres – our own “spider silk”, lightweight yet stronger than steel. The work may even help us fight diseases like Alzheimer’s, where amyloid fibrils present in the brain have structures similar to the clustered spidroin fibres.