Molecular and Structural Properties of Spider Silk

Abstract

Spider silk has extraordinary mechanical properties, outperforming some of the best-known man-made and natural materials in the world. Over the past 300 million years, spiders have evolved to produce high performance fibers that are uniquely designed to encompass high-tensile strength and toughness. As scientists have pursued a deeper understanding of the biochemical properties of silk, investigators have discovered that spiders are capable of spinning multiple fiber types that exhibit diverse mechanical properties. These differences are largely attributed to unique combinations of silk proteins spun into the fibers and the primary, secondary, and tertiary structure of the silk proteins in the fibers. Because of the outstanding properties of spider silk and its potential to serve as a next generation biomaterial, researchers have been racing to replicate synthetic spider silk. In this book chapter, we summarize the molecular and chemical properties of different silk types in spiders, their biological functions, and mechanisms of silk extrusion, assembly, and post-spin draw. We also discuss strategies that are being implemented for large-scale production of recombinant silk proteins using a variety of heterologous expression systems, explore purification protocols, and review the different spinning methodologies that are being applied for synthetic silk production.