Native-sized spider silk proteins synthesized in planta via intein-based multimerization

Area of Science:

• Biomaterials Science
• Synthetic Biology
• Plant Biotechnology

Background:

• Spider silk possesses remarkable properties like tensile strength and elasticity due to its repetitive protein motifs.
• Producing native-sized spider silk proteins is crucial for its application as a bio-based material.
• Current methods face challenges with the genetic and transcriptional stability of highly repetitive transgenes.

Purpose of the Study:

• To develop a novel method for synthesizing high molecular weight, native-sized spider silk proteins in planta.
• To overcome limitations associated with highly repetitive transgenes in producing spider silk proteins.
• To demonstrate the potential of assembled spider silk proteins as a biomaterial.

Main Methods:

• Production of spider silk flagelliform protein (FLAG) monomers in the endoplasmic reticulum of tobacco plant leaf cells.
• Utilizing an intein-based posttranslational protein fusion technology for protein ligation.
• Employing intein-mediated trans-splicing in planta to assemble FLAG monomers into large multimers.

Main Results:

• Successfully produced synthetic spider silk proteins exceeding 250 kDa, significantly larger than previously achieved.
• Demonstrated the formation of large multimers through the repeated ligation of FLAG monomers.
• The resulting multimeric structures self-assembled into microfibers, indicating biomaterial potential.

Conclusions:

• Intein-mediated trans-splicing in planta offers a stable and efficient method for producing high molecular weight spider silk proteins.
• This approach avoids the need for highly repetitive transgenes, enhancing genetic and transcriptional stability.
• The synthesized spider silk microfibers show significant potential for various biomaterial applications.