Protein's strength lies in h-bond cooperation

Geometric confinement in clusters enhances robustness of materials like spider silk

This figure shows the structure of a beta-sheet protein, Z1-Z2 telethonin complex, in the giant muscle protein titin. The inset shows the orientation of the protein backbone of three beta... Click here for more information.

CAMBRIDGE, Mass. — Researchers in Civil and Environmental Engineering at MIT reveal that the strength of a biological material like spider silk lies in the specific geometric configuration of structural proteins, which have small clusters of weak hydrogen bonds that work cooperatively to resist force and dissipate energy.

This structure makes the lightweight natural material as strong as steel, even though the “glue” of hydrogen bonds that hold spider silk together at the molecular level is 100 to 1,000 times weaker than the powerful glue of steel’s metallic bonds or even Kevlar’s covalent bonds.

Based on theoretical modeling and large-scale atomistic simulations implemented on supercomputers, this new understanding of exactly how a protein’s configuration enhances a material’s strength could help engineers create new materials that mimic spider silk’s lightweight robustness. It could also impact research on muscle tissue and amyloid fibers found in brain tissue.

“Our hope is that by understanding the mechanics of materials at the atomistic level, we will be able to one day create a guiding principle that will direct the synthesis of new materials,” said Professor Markus Buehler, lead researcher on the work.