Enhanced proteolytic stability and distinct mechanisms of a D-amino acid-modified antimicrobial peptide against Pseudomonas aeruginosa.
D-amino acid-modified antimicrobial peptides just took a step up in the fight against Pseudomonas aeruginosa. Thai researchers engineered dPA-13, a version of the classic 13-mer AMP PA-13, using only D-amino acids. This change makes a huge difference: dPA-13 shrugs off protease attacks that normally chew up standard peptides, holding its ground longer in harsh biological environments.
Sci Rep
by Khlaychinda S, Suriya U, Roytrakul S et al.
“Enhanced proteolytic stability and distinct mechanisms of a D-amino acid-modified antimicrobial peptide against Pseudomonas aeruginosa. Khlaychinda S(1), Suriya U(2), Roytrakul S(3), Aunpad R(4)(5). Author information: (1)Graduate Program in Biomedical Sciences, Faculty of Allied Health Sciences, Thammasat University, Pathum Thani, 12120, Thailand. (2)Department of Biochemistry, Faculty of Science, Mahidol University, Bangkok, 10400, Thailand. (3)National Center for Genetic Engineering and Biotechnology, National Science and Technology Development Agency, Pathum Thani, 12120, Thailand. (4)Graduate Program in Biomedical Sciences, Faculty of Allied Health Sciences, Thammasat University, Pathum Thani, 12120, Thailand. aratchan@tu.ac.th. (5)Thammasat University Research Unit in Antimicrobial Agent and Application, Thammasat University, Pathum Thani, 12120, Thailand. aratchan@tu.ac.th. Antimicrobial peptides (AMPs) are promising alternatives to conventional antibiotics for the treatment of multidrug-resistant (MDR) pathogens; however, their clinical translation is limited by proteolytic degradation. We developed dPA-13, an all-D-enantiomer of the 13-mer AMP PA-13, to improve resistance. dPA-13 exhibited potent bactericidal activity against Pseudomonas aeruginosa, superior protease stability, and a favorable safety profile. Confocal imaging and comparative proteomics revealed distinct mechanistic differences: while PA-13 localized to the membrane, dPA-13 exhibited enhanced cytoplasmic translocation. Proteomic analysis showed dPA-13 triggers a comprehensive cellular response, upregulating oxidoreductases (e.g., catalase), DNA repair machinery, and metal-ion binding proteins, while downregulating metabolic enzymes, transport permeases, and virulence factors (PilT and flagellar systems). Molecular docking corroborated these shifts, identifying high binding affinities toward critical targets, notably PilT, stabilized by specific electrostatic and hydrogen-bonding motifs at Glu394 and His397. Furthermore, P. aeruginosa developed resistance to dPA-13 significantly slower than to ciprofloxacin. Collectively, dPA-13 is a proteolytically robust, dual-action antimicrobial that disrupts both membrane integrity and intracellular homeostasis, positioning it as a promising candidate for recalcitrant MDR infections. © 2026. The Author(s). Conflict of interest statement: Declarations. Competing interests: The authors declare no competing interests.”
Key takeaway: dPA-13 packs a one-two punch. First, it wrecks the bacterial membrane. Second, unlike its parent PA-13 (which hangs out at the surface), dPA-13 blasts through into the cytoplasm. Inside, it triggers a cellular panic—upregulating defenses like catalase and DNA repair proteins, while also kneecapping core metabolic and transport processes. Virulence factors, including PilT and flagellar systems, get downregulated. The peptide’s unique structure gives it a strong binding affinity for these molecular targets, especially the PilT protein.
Other highlights researchers will care about:
dPA-13 kills P. aeruginosa fast, and bacteria develop resistance much slower than with traditional antibiotics like ciprofloxacin.
Proteolytic stability means dPA-13 survives longer in testing, making it more practical for real-world research.
Safety profile looks promising so far, according to early data.
Antimicrobial peptides are back in the spotlight for anyone looking to beat multidrug-resistant pathogens. If you’re exploring alternatives to antibiotics or working with D-amino acid-modified sequences, this study should be on your radar. For more on antimicrobial peptide mechanisms and applications, check out the peptide research index.
Peptide engineering like this is changing the research game—stay tuned.
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