A novel protein purification scheme based on salt inducible self-assembling peptides

Area of Science:

• Biochemistry
• Molecular Biology
• Biotechnology

Background:

• Protein purification is essential but often costly and time-consuming.
• Previous cleavable self-aggregating tag (cSAT) schemes facilitated protein purification.
• This study introduces a novel cSAT utilizing salt-inducible self-assembling peptides.

Purpose of the Study:

• To develop and validate a novel cSAT system employing salt-inducible self-assembling peptides.
• To enable soluble protein expression followed by controlled aggregation and purification.
• To offer an efficient and tag-free protein purification method.

Main Methods:

• A fusion protein incorporating a salt-inducible self-assembling peptide (MpA) and an intein was designed.
• Low salt concentrations maintained protein solubility, while salt addition induced MpA-mediated aggregation.
• Intein-mediated cleavage released the target protein, followed by purification.

Main Results:

• Four proteins and peptides were successfully purified with yields of 12-87 mg/L.
• Purification yields and purity (72-97%) were comparable to the His-tag method.
• Further chromatography increased purity to over 99%.

Conclusions:

• Salt-inducible self-assembling peptides provide a controllable aggregation tag for protein purification.
• This method is advantageous for applications requiring soluble target protein expression.
• The cSAT system demonstrates significant potential for efficient protein separation.