Cell-free synthesis system suitable for disulfide-containing proteins.

Area of Science:

• Biochemistry
• Molecular Biology
• Protein Engineering

Background:

• Secreted proteins with multiple disulfide bonds are crucial therapeutic targets.
• Cell-based expression systems often face challenges like low yield and inefficiency for these proteins.
• Cell-free (in vitro) protein synthesis offers an open system for controlled protein folding.

Purpose of the Study:

• To develop an efficient cell-free synthesis system for disulfide-containing proteins.
• To produce functional proteins suitable for Nuclear Magnetic Resonance (NMR) analyses.
• To overcome limitations of traditional cell-based expression methods.

Main Methods:

• Utilized an Escherichia coli (E. coli) cell lysate-based cell-free synthesis system.
• Employed a glutathione buffer to facilitate disulfide bond formation.
• Incorporated disulfide isomerase (DsbC) to catalyze correct disulfide bond shuffling.
• Synthesized (15)N-labeled bovine pancreatic trypsin inhibitor (BPTI) and human lysozyme C (LYZ).

Main Results:

• Successfully synthesized milligram quantities of functional BPTI and LYZ.
• NMR spectra confirmed proper protein folding.
• Functional analyses demonstrated catalytic activity of the synthesized proteins.
• Achieved efficient production of complex, disulfide-containing proteins.

Conclusions:

• The developed cell-free system is highly effective for producing functional, disulfide-containing proteins.
• This method provides a valuable alternative to cell-based systems for protein production.
• The system is suitable for generating proteins required for structural and functional studies, including NMR analysis.