Intrinsically disordered linkers and terminal domains codrive aciniform spidroin self-assembly through liquid-liquid...

Area of Science:

• Biomaterials Science
• Protein Engineering
• Structural Biology

Background:

• Aciniform silk, a tough and elastic protein fiber, is crucial for spiders.
• The self-assembly mechanism of aciniform spidroin (AcSp1) is not well understood.
• Previous research focused on other silk types like ampullate and eggcase silks.

Purpose of the Study:

• To elucidate the molecular mechanism of AcSp1 self-assembly.
• To investigate the role of intrinsically disordered linkers and the N-terminal domain (NTD) in AcSp1 assembly.
• To develop a method for fabricating artificial aciniform fibers.

Main Methods:

• Studied AcSp1 assembly driven by intrinsically disordered linkers via liquid-liquid phase separation.
• Analyzed N-terminal domain (NTD) dimerization and tetramerization across physiological pH.
• Investigated hierarchical assembly of AcSp1-NTD using hydrophobic and electrostatic interactions.

Main Results:

• Intrinsically disordered linkers drive AcSp1 assembly through liquid-liquid phase separation.
• AcSp1-NTD exhibits pH-independent dimerization and concentration-dependent tetramerization.
• Hierarchical assembly of AcSp1-NTD, mediated by hydrophobic and electrostatic interactions, enhances phase separation.

Conclusions:

• AcSp1 assembly is governed by a molecular strategy involving intrinsically disordered linkers and NTD interactions.
• A novel, fully aqueous spinning method was developed for artificial aciniform fiber production.
• Findings provide a foundation for creating advanced elastic and tough silk-based biomaterials.