Dataset Information

Macrocyclic Antimicrobial Peptides Engineered from ?-Conotoxin.

ABSTRACT: The potent calcium channel blocker ?-conotoxin MVIIA is a linear cystine-knot peptide with multiple basic amino acids at both termini. This work shows that macrocyclization of MVIIA linking two positive-charge terminal clusters as a contiguous segment converts a conotoxin into an antimicrobial peptide. In addition, conversion of disulfide bonds to amino butyric acids improved the antimicrobial activity of the cyclic analogs. Ten macrocyclic analogs, with or without disulfide bonds, were prepared by both Boc and Fmoc chemistry using native chemical ligation. All cyclic analogs were active against selected Gram-positive and Gram-negative bacteria with minimal inhibitory concentrations in a low ?M range. In contrast, MVIIA and its linear analog were inactive at concentrations up to 0.5 mM. The cyclic analogs also showed 2 to 3-fold improved chemotactic activity against human monocytes THP-1 compared with MVIIA. Reduction of molecular stability against thermal and acid treatment due to the reduced number of disulfide crosslinks can be partly restored by backbone cyclization. Together, these results show that macrocyclization and side chain modification of a linear conopeptide lead to a gain-of-function, which brings a new perspective in designing and engineering of peptidyl therapeutics.

SUBMITTER: Hemu X

PROVIDER: S-EPMC5470054 | biostudies-literature | 2017

REPOSITORIES: biostudies-literature

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Macrocyclic Antimicrobial Peptides Engineered from ω-Conotoxin.

Hemu Xinya X Tam James P JP

Current pharmaceutical design 20170101 14

The potent calcium channel blocker ω-conotoxin MVIIA is a linear cystine-knot peptide with multiple basic amino acids at both termini. This work shows that macrocyclization of MVIIA linking two positive-charge terminal clusters as a contiguous segment converts a conotoxin into an antimicrobial peptide. In addition, conversion of disulfide bonds to amino butyric acids improved the antimicrobial activity of the cyclic analogs. Ten macrocyclic analogs, with or without disulfide bonds, were prepared ...[more]

PMID: 28245769

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Project description:Helicobacter pylori is the primary cause of 78% of gastric cancer cases, providing an opportunity to prevent cancer by controlling a single bacterial pathogen within the complex gastric microbiota. We developed highly selective antimicrobial agents against H. pylori by fusing an H. pylori-binding guide peptide (MM1) to broad-spectrum antimicrobial peptides. The common dairy probiotic Lactococcus lactis was then engineered to secrete these guided antimicrobial peptides (gAMPs). When co-cultured in vitro with H. pylori, the gAMP probiotics lost no toxicity compared to unguided AMP probiotics against the target, H. pylori, while losing >90% of their toxicity against two tested off-target bacteria. To test binding to H. pylori, the MM1 guide was fused to green fluorescent protein (GFP), resulting in enhanced binding compared to unguided GFP as measured by flow cytometry. In contrast, MM1-GFP showed no increased binding over GFP against five different off-target bacteria. These highly selective gAMP probiotics were then tested by oral gavage in mice infected with H. pylori. As a therapy, the probiotics outperformed antibiotic treatment, effectively eliminating H. pylori in just 5 days, and also protected mice from challenge infection as a prophylactic. As expected, the gAMP probiotics were as toxic against H. pylori as the unguided AMP probiotics. However, a strong rebound in gastric species diversity was found with both the selective gAMP probiotics and the non-selective AMP probiotics. Eliminating the extreme microbial dysbiosis caused by H. pylori appeared to be the major factor in diversity recovery. IMPORTANCE Alternatives to antibiotics in the control of Helicobacter pylori and the prevention of gastric cancer are needed. The high prevalence of H. pylori in the human population, the induction of microbial dysbiosis by antibiotics, and increasing antibiotic resistance call for a more sustainable approach. By selectively eliminating the pathogen and retaining the commensal community, H. pylori control may be achieved without adverse health outcomes. Antibiotics are typically used as a therapeutic post-infection, but a more targeted, less disruptive approach could be used as a long-term prophylactic against H. pylori or, by extension, against other gastrointestinal pathogens. Furthermore, the modular nature of the guided antimicrobial peptide (gAMP) technology allows for the substitution of different guides for different pathogens and the use of a cocktail of gAMPs to avoid the development of pathogen resistance.

Dataset Information

Macrocyclic Antimicrobial Peptides Engineered from ?-Conotoxin.

Publications

Macrocyclic Antimicrobial Peptides Engineered from ω-Conotoxin.

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