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Hilpert K, Gani J, Rumancev C, Simpson N, Lopez-Perez PM, Garamus VM, von Gundlach AR, Markov P, Scocchi M, Mikut R, Rosenhahn A. Rational Designed Hybrid Peptides Show up to a 6-Fold Increase in Antimicrobial Activity and Demonstrate Different Ultrastructural Changes as the Parental Peptides Measured by BioSAXS. Front Pharmacol 2021; 12:769739. [PMID: 34966279 PMCID: PMC8711299 DOI: 10.3389/fphar.2021.769739] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2021] [Accepted: 11/12/2021] [Indexed: 11/27/2022] Open
Abstract
Antimicrobial peptides (AMPs) are a promising class of compounds being developed against multi-drug resistant bacteria. Hybridization has been reported to increase antimicrobial activity. Here, two proline-rich peptides (consP1: VRKPPYLPRPRPRPL-CONH2 and Bac5-v291: RWRRPIRRRPIRPPFWR-CONH2) were combined with two arginine-isoleucine-rich peptides (optP1: KIILRIRWR-CONH2 and optP7: KRRVRWIIW-CONH2). Proline-rich antimicrobial peptides (PrAMPs) are known to inhibit the bacterial ribosome, shown also for Bac5-v291, whereas it is hypothesized a “dirty drug” model for the arginine-isoleucine-rich peptides. That hypothesis was underpinned by transmission electron microscopy and biological small-angle X-ray scattering (BioSAXS). The strength of BioSAXS is the power to detect ultrastructural changes in millions of cells in a short time (seconds) in a high-throughput manner. This information can be used to classify antimicrobial compounds into groups according to the ultrastructural changes they inflict on bacteria and how the bacteria react towards that assault. Based on previous studies, this correlates very well with different modes of action. Due to the novelty of this approach direct identification of the target of the antimicrobial compound is not yet fully established, more research is needed. More research is needed to address this limitation. The hybrid peptides showed a stronger antimicrobial activity compared to the proline-rich peptides, except when compared to Bac5-v291 against E. coli. The increase in activity compared to the arginine-isoleucine-rich peptides was up to 6-fold, however, it was not a general increase but was dependent on the combination of peptides and bacteria. BioSAXS experiments revealed that proline-rich peptides and arginine-isoleucine-rich peptides induce very different ultrastructural changes in E. coli, whereas a hybrid peptide (hyP7B5GK) shows changes, different to both parental peptides and the untreated control. These different ultrastructural changes indicated that the mode of action of the parental peptides might be different from each other as well as from the hybrid peptide hyP7B5GK. All peptides showed very low haemolytic activity, some of them showed a 100-fold or larger therapeutic window, demonstrating the potential for further drug development.
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Affiliation(s)
- Kai Hilpert
- Institute of Infection and Immunology, St. George's, University of London, London, United Kingdom
| | - Jurnorain Gani
- Institute of Infection and Immunology, St. George's, University of London, London, United Kingdom
| | - Christoph Rumancev
- Laboratory Analytical Chemistry - Biointerfaces, Ruhr University Bochum, Bochum, Germany
| | - Nathan Simpson
- Institute of Infection and Immunology, St. George's, University of London, London, United Kingdom
| | | | | | | | - Petar Markov
- European Molecular Biology Laboratory, Hamburg Outstation, Hamburg, Germany
| | - Marco Scocchi
- Department of Life Sciences, University of Trieste, Trieste, Italy
| | - Ralf Mikut
- Institute for Automation and Applied Informatics (IAI), Karlsruhe Institute of Technology (KIT), Karlsruhe, Germany
| | - Axel Rosenhahn
- Laboratory Analytical Chemistry - Biointerfaces, Ruhr University Bochum, Bochum, Germany
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