Structural and Functional Mimicry of the Antimicrobial Defensin Plectasin by Analogues with Engineered Backbone...

Area of Science:

• Biochemistry
• Microbiology
• Drug Discovery

Background:

• Antibiotic resistance necessitates novel antimicrobial agents.
• Lipid II-binding natural products, like vancomycin and plectasin, show promise.
• Ribosomally produced miniproteins (like plectasin) are susceptible to proteases.

Purpose of the Study:

• To develop proteomimetic variants of plectasin with enhanced stability.
• To investigate the impact of artificial backbone connectivity on plectasin's structure and function.
• To create novel antimicrobial agents to combat resistant bacteria.

Main Methods:

• Systematic incorporation of artificial backbone connectivity into the plectasin domain.
• Iterative secondary-structure-based design.
• Characterization of tertiary fold, antimicrobial activity, and mammalian cell toxicity.
• Assessment of oxidative folding efficiency and proteolytic hydrolysis resistance.

Main Results:

• Developed a plectasin variant with a tertiary fold indistinguishable from the natural product.
• Achieved potent activity against Gram-positive bacteria with low mammalian cell toxicity.
• Demonstrated improved oxidative folding efficiency and resistance to proteolytic hydrolysis.
• Confirmed the efficacy of backbone modification for enhancing protein stability.

Conclusions:

• Proteomimetic design strategies can yield stable and potent antimicrobial agents.
• Backbone modification enhances the stability and folding of disulfide-rich protein scaffolds.
• This approach broadens the possibilities for designing protein mimetics with novel functions.