Ultrastable de novo SuperMyo proteins enable high-performance macroscopic fibers from minimal repeats

Conventional routes to strong protein fibers rely on the assembly of high-molecular-weight polymers, where mechanical performance is achieved by increasing the number of tandem repeats within the polypeptide chain. This repeat-number strategy inherently complicates production and limits scalability. Here, we introduce a contrasting paradigm in which macroscopic strength is derived not from chain length, but from the increased intrinsic mechanostability of each repeating unit. We implement this using computationally designed immunoglobulin-domain-based SuperMyo proteins, whose force-bearing β-strands are engineered to form ultra-dense hydrogen-bond networks, yielding unfolding forces nearly double those of natural immunoglobulin domains at a pulling speed of 1000 nm s−1. When assembled into minimal tetrameric constructs (only four repeats), these designed units retain their high nanomechanical stability. Processed via wet-spinning, the tetramers form continuous macroscopic fibers with a tensile strength up to 372 MPa and a toughness of 61 MJ m⁻³. Crucially, this performance matches or exceeds that of previously reported fibers spun from polymers containing far more repeats (e.g., 64-mers). Structural analyses confirm that the enhanced stability of the monomers promotes superior β-sheet crystallization and alignment during fiber formation. By demonstrating that engineering the mechanical stability of protein building blocks is a potential strategy for producing strong protein fibers from low-repeat-number constructs, this work establishes a more efficient and scalable foundation for manufacturing high-performance protein-based materials. High-performance biofuels require a well-defined flash point, yet the coexistence of pentanol isomers can introduce ignition-point variations that compromise fuel performance. Here, the authors present an electrochemiluminescence shunt strategy based on a bifunctional catalytic system that exploits the distinct reactive oxygen species scavenging properties of pentanol isomers. The approach generates differential anodic and cathodic luminol signals, enabling their precise discrimination and providing a powerful tool for fuel-quality assessment