Designed Trp-Cage Proteins with Antimicrobial Activity and Enhanced Stability.

Area of Science:

• Biochemistry
• Antimicrobial drug development
• Protein engineering

Background:

• Alpha-helical antimicrobial peptides (αAMPs) show promise against antibiotic-resistant bacteria.
• A major limitation of αAMPs is their poor bioavailability due to rapid enzymatic degradation.
• Existing strategies to enhance αAMP stability often involve non-natural amino acids.

Purpose of the Study:

• To develop a novel strategy for increasing the protease resistance of αAMPs.
• To enhance the antimicrobial activity and pharmacokinetic properties of αAMPs for therapeutic applications.
• To create a protease-resistant antimicrobial peptide using a fusion approach applicable to biosynthesis.

Main Methods:

• Fusion of the 12-residue αAMP KR-12 with a Trp-cage domain.
• Structural analysis and proteolytic degradation assays to assess peptide stability.
• Evaluation of antimicrobial activity against bacteria and hemolytic activity against red blood cells.

Main Results:

• The Trp-cage fusion induced a stable α-helical structure in the KR-12 peptide.
• The resulting antimicrobial Trp-cage demonstrated significantly enhanced resistance to protease degradation.
• The engineered peptide exhibited increased antibacterial activity in the presence of NaCl, with negligible hemolytic activity.

Conclusions:

• Fusion with a Trp-cage domain is an effective strategy to improve αAMP stability and efficacy.
• This approach overcomes limitations of previous methods by utilizing natural amino acids, enabling biosynthetic production.
• The enhanced antimicrobial Trp-cage represents a promising candidate for developing new anti-infective therapeutics.