Tyrosine-based "activatable pro-tag": enzyme-catalyzed protein capture and release

Area of Science:

• Biochemistry
• Biotechnology
• Materials Science

Background:

• Traditional protein recovery often relies on chromatography, which can be complex and time-consuming.
• Enzymatic methods offer potential for more specific and efficient biomolecule manipulation.

Purpose of the Study:

• To develop and demonstrate a non-chromatographic, enzyme-mediated protein capture and release system.
• To utilize the stimuli-responsive properties of chitosan for protein purification.

Main Methods:

• Enzymatic activation of protein tyrosine residues using tyrosinase for covalent conjugation to chitosan.
• Engineering proteins with a penta-tyrosine "pro-tag" to enhance capture efficiency.
• Exploiting the pH-responsive solubility of chitosan for protein purification.
• Releasing captured proteins via enzymatic cleavage (enterokinase) or chitosan backbone hydrolysis (chitosanase).

Main Results:

• Enzymatic activation is essential for protein capture onto chitosan.
• A penta-tyrosine tag significantly enhances protein capture (approximately five-fold).
• The pH-responsive nature of the chitosan conjugate facilitates purification.
• Successful release of model green fluorescent protein (GFP) using both enterokinase and chitosanase.

Conclusions:

• Enzymatic capture and release using tyrosinase and chitosan provides an effective, non-chromatographic method for protein recovery.
• The penta-tyrosine "pro-tag" offers a robust strategy for enhancing protein immobilization.
• This approach simplifies protein purification directly from complex biological mixtures like cell lysates.