Microbially Synthesized Polymeric Amyloid Fiber Promotes β-Nanocrystal Formation and Displays Gigapascal Tensile Strength

Jingyao Li, Yaguang Zhu, Han Yu, Bin Dai, Young Shin Jun, Fuzhong Zhang

Research output: Contribution to journalArticlepeer-review

33 Scopus citations

Abstract

The ability of amyloid proteins to form stable β-sheet nanofibrils has made them potential candidates for material innovation in nanotechnology. However, such a nanoscale feature has rarely translated into attractive macroscopic properties for mechanically demanding applications. Here, we present a strategy by fusing amyloid peptides with flexible linkers from spidroin; the resulting polymeric amyloid proteins can be biosynthesized using engineered microbes and wet-spun into macroscopic fibers. Using this strategy, fibers from three different amyloid groups were fabricated. Structural analyses unveil the presence of β-nanocrystals that resemble the cross-β structure of amyloid nanofibrils. These polymeric amyloid fibers have displayed strong and molecular-weight-dependent mechanical properties. Fibers made of a protein polymer containing 128 repeats of the FGAILSS sequence displayed an average ultimate tensile strength of 0.98 ± 0.08 GPa and an average toughness of 161 ± 26 MJ/m3, surpassing most recombinant protein fibers and even some natural spider silk fibers. The design strategy and the biosynthetic approach can be expanded to create numerous functional materials, and the macroscopic amyloid fibers will enable a wide range of mechanically demanding applications.

Original languageEnglish
Pages (from-to)11843-11853
Number of pages11
JournalACS nano
Volume15
Issue number7
DOIs
StatePublished - Jul 27 2021

Keywords

  • amyloid
  • protein engineering
  • protein fibers
  • silk
  • wet spinning
  • wide-angle X-ray diffraction

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