糖心视频

Different species of spiders produce different silks that serve different purposes, from floating on air to cradling eggs. The triangle weaver spider, Hyptiotes cavatus, weaves and holds a three-sided web under tension, which it releases the moment prey flies into the web, quickly tangling the prey in the spring-loaded threads. Thus, the web can move much faster than any muscle in the spider's body, illustrating how silk can amplify a spider's abilities.

inPNAS Nexus, Jessica Garb and colleagues sequenced the genome of Hyptiotes cavatus to learn more. Proline is an amino acid with a ring-shaped structure that has been shown to influence the extensibility, supercontraction, and elasticity of spider silk.

The authors found that the triangle weaver spider has an expanded set of MaSp2 genes, which encode silks rich in proline, resulting in dragline silk with among the highest known proline content: up to 24.3% as calculated by characterizing amino acid composition directly from draglines.

The triangle weaver spider's silk proteins share characteristics with those produced by Darwin's bark spider (Caerostris darwini), but the spiders are distantly related, suggesting convergent evolution of proteins involved in silk extensibility. According to the authors, understanding how these proline-rich protein sequences enable the spring-loaded mechanism may inform design of novel high-performance biomaterials.