A joint team from King’s College London and San Diego State University (SDSU) has identified the specific molecular interactions that give spider silk its extraordinary combination of strength and flexibility. The findings were published on February 6, 2026 in the journal Proceedings of the National Academy of Sciences.
The study names two amino acids — arginine and tyrosine — as the chemical triggers responsible for the process. When spider silk proteins are still stored as a thick liquid inside the silk gland, these two amino acids pair up and pull surrounding proteins into clusters. That pairing persists as the liquid is drawn into solid fiber, forming the nanostructure that accounts for the material’s mechanical performance.
Spider dragline silk, the type used to build web frameworks and support the spider’s weight, outperforms both steel and Kevlar on a pound-for-pound basis. Scientists have long understood that the silk proteins cluster into liquid-like droplets before solidifying, but the molecular steps connecting those early droplets to the finished fiber’s strength had not been mapped.
To trace the process, the team combined molecular dynamics simulations, AlphaFold3 structural modeling, and nuclear magnetic resonance (NMR) spectroscopy. Chris Lorenz, Professor of Computational Materials Science at King’s College London, said the results provide “an atomistic-level explanation of how disordered proteins assemble into highly ordered, high-performance structures.”
Lorenz pointed to lightweight protective clothing, aircraft components, biodegradable medical implants, and soft robotics as areas that could benefit from fibers engineered using these principles.
The research also has implications for neuroscience. Gregory Holland, a professor of physical and analytical chemistry at SDSU, noted that the same arginine–tyrosine interactions appear in neurotransmitter receptors and hormone signaling pathways. The way silk proteins undergo phase separation and form β-sheet-rich structures mirrors mechanisms observed in neurodegenerative conditions such as Alzheimer’s disease. Holland said silk offers a cleaner, evolutionarily tested system for studying how those protein aggregation processes can be controlled.
