How Do Spiders Produce and Use Silk?
Scientists have long tried to determine how spiders produce and use silk. The silk of spiders is a polypeptide, which consists of repetitive DNA sequences and chains of amino acids. A silk strand can stretch up to 140 percent of its length without breaking. It is five times stronger than steel.
Spiders use silk to suspend themselves from the earth’s surface. They also use it to wrap up prey. In addition, they sip water droplets on their webs to quench their thirst. These silks contain proteins, nucleic acids, carbohydrates, and vitamin K.
Some spiders have been shown to vary the content of amino acids in their silk. This may reflect their diet.
Some researchers have tried to replicate the components of silk in laboratory experiments. However, their results have been less than promising.
Silks are complex proteins that can be difficult to reproduce. Several factors influence the folding and unfolding of the protein. They include the structure of the molecule and its storage solutions.
To determine the molecular structure of the silk, X-ray microdiffraction was used. Synchrotron radiation X-ray microdiffraction allowed the amorphous and crystalline regions of the silk to be distinguished.
Different elasticity of the amorphous and crystalline regions is due to the presence of glycine. Each amorphous region has four to nine alanines connected together. Similarly, the crystalline regions contain three alanines connected to each other.
Because of the unique properties of spider silk, it is believed that mechanical forces play a role in the spinning process. These forces may include frictional forces.