Zbasic: a purification tag for selective ion-exchange recovery.

Area of Science:

• Biochemistry
• Protein Chemistry
• Recombinant Protein Production

Background:

• Protein purification is crucial for recombinant protein applications.
• Existing purification tags have limitations, especially for proteins expressed in inclusion bodies.
• Cation-exchange chromatography is a common purification method.

Purpose of the Study:

• To introduce and validate the Zbasic protein domain as a versatile purification tag.
• To demonstrate Zbasic's utility for both soluble and insoluble recombinant proteins.
• To develop protocols for purification, refolding, and tag removal.

Main Methods:

• Engineering of a highly charged Zbasic domain from a Protein A-derived sequence.
• Application of Zbasic-tagged proteins in cation-exchange chromatography under native and denaturing conditions.
• Development of integrated purification and solid-phase refolding protocols.
• Enzymatic removal of the Zbasic tag for native protein recovery.

Main Results:

• Zbasic enables selective capture of tagged proteins on cation exchangers at physiological pH.
• The tag is effective for purifying proteins solubilized from inclusion bodies under denaturing conditions.
• Integrated purification and solid-phase refolding protocols were successfully established.
• Enzymatic tag removal yielded native target proteins.

Conclusions:

• The Zbasic domain is a highly effective and flexible purification tag for recombinant proteins.
• It offers advantages for purifying proteins from inclusion bodies and enables efficient refolding.
• Zbasic facilitates a streamlined process for obtaining native target proteins.