A general method for retrieving the components of a genetically engineered fusion protein

Area of Science:

• Biotechnology
• Molecular Biology
• Protein Chemistry

Background:

• Recombinant protein production often requires efficient purification strategies.
• Fusion proteins are commonly used to facilitate protein expression and purification.
• Developing methods for site-specific protein cleavage is crucial for obtaining functional proteins.

Purpose of the Study:

• To construct Escherichia coli expression vectors for synthesizing bovine growth hormone (bGH) fusion proteins.
• To investigate the acid-labile cleavage of an aspartyl-proline (Asp-Pro) dipeptide linker.
• To assess the biological activity of released bGH.

Main Methods:

• Construction of expression vectors in E. coli encoding bGH fusion proteins with an Asp-Pro dipeptide linker.
• Utilizing the Bam HI recognition site (GGATCC) to introduce the Asp-Pro codons (GAT-CCX).
• Cleavage of fusion proteins at low pH with guanidine hydrochloride to release bGH.

Main Results:

• Successfully synthesized two distinct bGH fusion proteins using the constructed vectors.
• Demonstrated specific release of the bGH moiety under low pH conditions, dependent on the Asp-Pro dipeptide.
• Confirmed that the released bGH retains anti-bGH immunoreactivity and growth hormone receptor binding ability in vitro.

Conclusions:

• The developed system enables the production of bGH fusion proteins with a cleavable linker in E. coli.
• Acid-labile cleavage at the Asp-Pro dipeptide site provides a specific method for releasing biologically active bGH.
• This approach offers a valuable tool for recombinant protein production and purification.