High Tensile Strength of Engineered β-Solenoid Fibrils via Sonication and Pulling

We present estimates of ultimate tensile strength (UTS) for two engineered β-solenoid protein mutant fibril structures (spruce budworm and Rhagium inquisitor antifreeze proteins) derived from sonication-based measurements and from force pulling molecular dynamics simulations, both in water. Sonication experiments generate limiting scissioned fibrils with a well-defined length-to-width correlation for the mutant spruce budworm protein and the resultant UTS estimate is 0.66 0.08 GPa. For fibrils formed from engineered R. inquisitor antifreeze protein, depending upon geometry, we estimate UTSs of 3.5 3.2–5.5 5.1 GPa for proteins with interfacial disulfide bonds, and 1.6 1.5–2.5 2.3 GPa for the reduced form.

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