Spinning Silk

Spider web

Web of Stegodyphus Social Spiders
Photo: Dr VB Whitehead

Major ampullate silk is secreted by the major ampullate gland of spiders. In the best studied systems two silk proteins differing in amino acid sequence and structure are secreted by the gland. The ratio of the two proteins is thought to affect the silk properties.

MA silk is produced in the MA gland which has a distal tail, a storage reservoir, and a duct to the outside that ends at a spigot to control release.  Silk proteins are secreted by cells lining the narrow tail of the MA gland. The proteins are stored in the reservoir at a pH between 6.8 and 7.0. pH affects the folding and structure of proteins. When a silk strand is released, protein from the reservoir travels down the duct to the spigot.  Within the duct the  pH of the silk solution acidifies from a neutral pH at the reservoir end to an acidic pH of about 5 near the spigot. The change in pH helps the silk to assemble into strands when they are released from the spigot.

Vollrath F, Knight DP. 2001. Liquid crystalline spinning of spider silk. Nature 410:541–48

About jjneal

Jonathan Neal is a retired Associate Professor of Entomology at Purdue University and author of the textbook, Living With Insects (2010). This blog is a forum to communicate about the intersection of insects with people and policy. This is a personal blog. The opinions and materials posted here are those of the author and are in no way connected with those of my employer.
This entry was posted in Biomaterials, by jjneal. Bookmark the permalink.

1 Response to Spinning Silk

  1. Pingback: Spinning Silk – Entomo Planet

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s