Purifying the hedgehog protein and its variants

Area of Science:

• Biochemistry
• Molecular Biology
• Protein Chemistry

Background:

• Sonic hedgehog (ShhN) is a crucial signaling protein involved in development.
• Understanding ShhN's post-translational modifications is key to its biological activity.
• Recombinant protein production requires optimized purification strategies.

Purpose of the Study:

• To investigate the impact of post-translational modifications on ShhN potency.
• To develop robust purification methods for ShhN and related proteins.
• To characterize ShhN's sensitivity to oxidation and degradation.

Main Methods:

• Purification of recombinant ShhN from diverse expression systems (E. coli, insect, yeast, mammalian cells).
• Analysis of post-translational modifications, including fatty acylation and proteolytic clipping.
• Development of oxidation-minimizing purification techniques.

Main Results:

• Fatty acylation of N-terminal cysteine residues increased ShhN potency up to 100-fold.
• Proteolytic clipping near the N-terminus led to complete loss of signaling activity.
• ShhN is highly sensitive to metal ion-induced oxidation, requiring protective measures.
• Purification methods were effective for ShhN and applicable to Indian and Desert hedgehog proteins.

Conclusions:

• Post-translational modifications, particularly fatty acylation, are critical for ShhN function.
• Proteolytic and oxidative degradation significantly impair ShhN activity.
• Developed purification strategies ensure high-potency ShhN and are broadly applicable to other hedgehog proteins.