Spidroin

These alanine blocks can stack to create crystalline structures in the fiber, linking different protein molecules together.

Glycine is present in different motifs, such as GGX and GPGXX (where X = A, L, Q, or Y), that also have specific secondary structures (3 10 helix and β-spiral, respectively).

N- and C-terminal domains share little resemblance, except that they are both rich in serine and both are largely amphipathic α-helical secondary structures.

[7] The C-terminal domain is involved in the organized transition from a soluble spidroin solution to an insoluble fiber during spinning.

[8] In the N-terminal domain, there are signal peptides which regulate spidroin secretion from silk gland cells.

Dragline silk is used not only to construct the outer frame and radii of the orb-shaped web but also as a hanging lifeline that allows the spider to evade and/or escape from predators.

As the gelatinous protein solution moves into the duct, the integral spidroins and glycoproteins are gradually distorted into long, thin, aligned figures with the direction of the flow.

In the last decade, much research has been done about spidroin protein and spider silk in order to take advantage of some of its properties, such as its elasticity and strength.

Recombinant spidroin has been successfully obtained in both eukaryotic and prokaryotic cells although there were some difficulties in the procedure due to the length of the gene sequence.

Thanks to expression and the cloning work, it is possible to obtain large-scale production of spidroin which provides new opportunities for the manufacture of new biomaterials.

[13] There have been attempts to generate transgenic tobacco and potato plants that express remarkable amounts of recombinant Nephila clavipes dragline proteins.

[1][10] In July 2020 a team of RIKΞN researchers report that they succeeded in using a genetically altered variant of R. sulfidophilum to produce spidroins.