A new research has shown the way in which spiders regulate the process of silk spinning.

Anna Rising and Jan Johansson of the Swedish University of Agricultural Sciences and Karolinska Institute showed that spiders have quite a challenging task in making the stretchy and lightweight material.

In order to produce silk, spidroins which are silk proteins are required to be converted from a soluble form to solid fibres with water as the solvent at a high speed and ambient temperatures.

Spidroins are big proteins, which are made up of 3,500 amino acids that mostly contain repetitive sequences but the vital bits for conversion of spidroins into silk are the ends.

The structure of spidroins is helical and unordered when they are stored as soluble proteins in the silk glands. When they are converted to silk, their structure completely changes to a form which has a high degree of mechanical stability. These changes are brought about by a pH gradient which is present between one end of the silk gland of spiders called the 'N-terminal domain' and the other, the 'C-terminal domain'.

The researchers found that the N-terminal domain had a tendency to pair up with other molecules at the beginning of the duct and it became stable as the acidity increased along the duct. On the other hand, the C-terminal domain destabilized with increase in the acidity content and unfolded in a gradual manner until the characteristic structure of silk was formed at the acidic pH of 5.5.

This mechanism very well explained how spider silk could be formed so quickly and smoothly within the spinning duct of these stunning organisms.

The researchers proposed a new model for silk formation by the spiders called the "lock and trigger" model. The knowledge of how spiders spin silk may give insights to humans into the natural ways of inhibiting the amyloid fibrils that are associated with diseases like dementia.