ijms-logo

Journal Browser

Journal Browser

Antimicrobial Peptides: Structure and Mechanism of Biological Activity: 3rd Edition

A special issue of International Journal of Molecular Sciences (ISSN 1422-0067). This special issue belongs to the section "Molecular Microbiology".

Deadline for manuscript submissions: 30 November 2024 | Viewed by 8451

Special Issue Editor


E-Mail Website
Guest Editor
Departamento de Nutrición y Ciencia de los Alimentos (NUTRYCIAL), Sección Departamental de Nutrición y Ciencia de los Alimentos (SD-NUTRYCIAL), Facultad de Veterinaria, Universidad Complutense de Madrid (UCM), Avenida Puerta de Hierro, s/n, 28040 Madrid, Spain
Interests: microbiology; antimicrobial peptides; synthetic biology; biotechnology; bacteriocins

Special Issue Information

Dear Colleagues,

Since the early 1960s, the resistance of microbes against antibiotics has been recognized as a potential global health issue. This issue is now critical due to the reemergence of several infectious diseases of microbial origin and prevalence of multidrug-resistant microbes. Antimicrobial peptides (AMPs) have offered a good potential for novel drugs against drug-resistant microbial organisms, and extensive research has been dedicated to the discovery, characterization, de novo design, and assessment of the antimicrobial activity of these peptides since the late 1980s. So far, more than 3000 AMPs have been characterized and documented. These peptides have diverse natural origins and are found in unicellular organisms (bacteria, archaea, protists, and fungi), plants, and animals. Close to 75% of AMPs are found in animals, ~11% in plants, and about the same number in bacteria. Based on the sequences of these naturally found peptides, new chemically modified synthetic peptides have been designed to enhance or modify the biological activity of the original peptides. AMPs are also diverse in their biological activities and can be multifunctional. In addition to their antimicrobial activity, AMPs can have other biological functions, such as antioxidant, anticancer, antimalarial, chemotactic (modulation of immune systems), and wound healing. The diversity of AMPs expands to their physicochemical properties, structure, and mechanism of biological activity, which are the foci of this Special Issue. Most, but not all, AMPs are positively charged, and negatively and neutrally charged peptides can also be found. AMPs have different structures (α-helix, β-sheet, turn, or nonspecific interconvertible dynamic structures), overall hydrophobicity and amphipathicity, and can be linear, cyclic, or a combination of both. Many AMPs interact with the lipid membranes of the microbial/nonmicrobial cells and destroy these cells by disrupting the osmotic balance across the membrane. Some AMPs can pass across cell membranes and interact with intracellular targets such as organelle membranes, receptor proteins, or DNA. In the late 1980s and during the 1990s, several models were proposed for the mechanism of interaction of AMPs with model cell membranes, which generally include self-association of peptides and/or peptide–lipid association from specific well-defined pores or to induce nonspecific leakage. The mechanisms of translocation of AMPs through cell membranes and their successive interaction with intracellular molecules are less investigated. Understanding and visualizing the structural dynamics (subtle and fast conformational changes prior to and after interaction with cell membranes) and the entirety of the complex biophysical nature of the mechanism of the biological activity of AMPs are essential steps toward the discovery and design of new antimicrobial peptide drugs.

Dr. Juan Borrero
Guest Editor

Manuscript Submission Information

Manuscripts should be submitted online at www.mdpi.com by registering and logging in to this website. Once you are registered, click here to go to the submission form. Manuscripts can be submitted until the deadline. All submissions that pass pre-check are peer-reviewed. Accepted papers will be published continuously in the journal (as soon as accepted) and will be listed together on the special issue website. Research articles, review articles as well as short communications are invited. For planned papers, a title and short abstract (about 100 words) can be sent to the Editorial Office for announcement on this website.

Submitted manuscripts should not have been published previously, nor be under consideration for publication elsewhere (except conference proceedings papers). All manuscripts are thoroughly refereed through a single-blind peer-review process. A guide for authors and other relevant information for submission of manuscripts is available on the Instructions for Authors page. International Journal of Molecular Sciences is an international peer-reviewed open access semimonthly journal published by MDPI.

Please visit the Instructions for Authors page before submitting a manuscript. There is an Article Processing Charge (APC) for publication in this open access journal. For details about the APC please see here. Submitted papers should be well formatted and use good English. Authors may use MDPI's English editing service prior to publication or during author revisions.

Keywords

  • antimicrobial peptides
  • mechanism of biological activity
  • functional diversity of peptides
  • structural analysis of peptides
  • dynamic conformation of peptides
  • lipid composition of the cell membrane
  • peptide–lipid interactions
  • peptide self-association
  • peptide-lipid complex formation
  • peptide–intracellular receptor interaction
  • peptide translocation through membrane
  • cell morphology
  • peptide interaction with infectious agents
  • surface properties of the cell
  • peptide interaction with the cell in vivo

Benefits of Publishing in a Special Issue

  • Ease of navigation: Grouping papers by topic helps scholars navigate broad scope journals more efficiently.
  • Greater discoverability: Special Issues support the reach and impact of scientific research. Articles in Special Issues are more discoverable and cited more frequently.
  • Expansion of research network: Special Issues facilitate connections among authors, fostering scientific collaborations.
  • External promotion: Articles in Special Issues are often promoted through the journal's social media, increasing their visibility.
  • e-Book format: Special Issues with more than 10 articles can be published as dedicated e-books, ensuring wide and rapid dissemination.

Further information on MDPI's Special Issue polices can be found here.

Related Special Issues

Published Papers (5 papers)

Order results
Result details
Select all
Export citation of selected articles as:

Research

19 pages, 2724 KiB  
Article
1,3,5-Triazine as Branching Connector for the Construction of Novel Antimicrobial Peptide Dendrimers: Synthesis and Biological Characterization
by Rotimi Sheyi, Jessica T. Mhlongo, Marta Jorba, Ester Fusté, Anamika Sharma, Miguel Viñas, Fernando Albericio, Paula Espinal and Beatriz G. de la Torre
Int. J. Mol. Sci. 2024, 25(11), 5883; https://doi.org/10.3390/ijms25115883 - 28 May 2024
Viewed by 961
Abstract
Peptides displaying antimicrobial properties are being regarded as useful tools to evade and combat antimicrobial resistance, a major public health challenge. Here we have addressed dendrimers, attractive molecules in pharmaceutical innovation and development displaying broad biological activity. Triazine-based dendrimers were fully synthesized in [...] Read more.
Peptides displaying antimicrobial properties are being regarded as useful tools to evade and combat antimicrobial resistance, a major public health challenge. Here we have addressed dendrimers, attractive molecules in pharmaceutical innovation and development displaying broad biological activity. Triazine-based dendrimers were fully synthesized in the solid phase, and their antimicrobial activity and some insights into their mechanisms of action were explored. Triazine is present in a large number of compounds with highly diverse biological targets with broad biological activities and could be an excellent branching unit to accommodate peptides. Our results show that the novel peptide dendrimers synthesized have remarkable antimicrobial activity against Gram-negative bacteria (E. coli and P. aeruginosa) and suggest that they may be useful in neutralizing the effect of efflux machinery on resistance. Full article
Show Figures

Figure 1

20 pages, 2433 KiB  
Article
Production of Pumilarin and a Novel Circular Bacteriocin, Altitudin A, by Bacillus altitudinis ECC22, a Soil-Derived Bacteriocin Producer
by Irene Lafuente, Ester Sevillano, Nuria Peña, Alicia Cuartero, Pablo E. Hernández, Luis M. Cintas, Estefanía Muñoz-Atienza and Juan Borrero
Int. J. Mol. Sci. 2024, 25(4), 2020; https://doi.org/10.3390/ijms25042020 - 7 Feb 2024
Cited by 4 | Viewed by 2208
Abstract
The rise of antimicrobial resistance poses a significant global health threat, necessitating urgent efforts to identify novel antimicrobial agents. In this study, we undertook a thorough screening of soil-derived bacterial isolates to identify candidates showing antimicrobial activity against Gram-positive bacteria. A highly active [...] Read more.
The rise of antimicrobial resistance poses a significant global health threat, necessitating urgent efforts to identify novel antimicrobial agents. In this study, we undertook a thorough screening of soil-derived bacterial isolates to identify candidates showing antimicrobial activity against Gram-positive bacteria. A highly active antagonistic isolate was initially identified as Bacillus altitudinis ECC22, being further subjected to whole genome sequencing. A bioinformatic analysis of the B. altitudinis ECC22 genome revealed the presence of two gene clusters responsible for synthesizing two circular bacteriocins: pumilarin and a novel circular bacteriocin named altitudin A, alongside a closticin 574-like bacteriocin (CLB) structural gene. The synthesis and antimicrobial activity of the bacteriocins, pumilarin and altitudin A, were evaluated and validated using an in vitro cell-free protein synthesis (IV-CFPS) protocol coupled to a split-intein-mediated ligation procedure, as well as through their in vivo production by recombinant E. coli cells. However, the IV-CFPS of CLB showed no antimicrobial activity against the bacterial indicators tested. The purification of the bacteriocins produced by B. altitudinis ECC22, and their evaluation by MALDI-TOF MS analysis and LC-MS/MS-derived targeted proteomics identification combined with massive peptide analysis, confirmed the production and circular conformation of pumilarin and altitudin A. Both bacteriocins exhibited a spectrum of activity primarily directed against other Bacillus spp. strains. Structural three-dimensional predictions revealed that pumilarin and altitudin A may adopt a circular conformation with five- and four-α-helices, respectively. Full article
Show Figures

Figure 1

17 pages, 6731 KiB  
Article
New N-Terminal Fatty-Acid-Modified Melittin Analogs with Potent Biological Activity
by Sheng Huang, Guoqi Su, Shan Jiang, Li Chen, Jinxiu Huang and Feiyun Yang
Int. J. Mol. Sci. 2024, 25(2), 867; https://doi.org/10.3390/ijms25020867 - 10 Jan 2024
Cited by 5 | Viewed by 1382
Abstract
Melittin, a natural antimicrobial peptide, has broad-spectrum antimicrobial activity. This has resulted in it gaining increasing attention as a potential antibiotic alternative; however, its practical use has been limited by its weak antimicrobial activity, high hemolytic activity, and low proteolytic stability. In this [...] Read more.
Melittin, a natural antimicrobial peptide, has broad-spectrum antimicrobial activity. This has resulted in it gaining increasing attention as a potential antibiotic alternative; however, its practical use has been limited by its weak antimicrobial activity, high hemolytic activity, and low proteolytic stability. In this study, N-terminal fatty acid conjugation was used to develop new melittin-derived lipopeptides (MDLs) to improve the characteristics of melittin. Our results showed that compared with native melittin, the antimicrobial activity of MDLs was increased by 2 to 16 times, and the stability of these MDLs against trypsin and pepsin degradation was increased by 50 to 80%. However, the hemolytic activity of the MDLs decreased when the length of the carbon chain of fatty acids exceeded 10. Among the MDLs, the newly designed analog Mel-C8 showed optimal antimicrobial activity and protease stability. The antimicrobial mechanism studied revealed that the MDLs showed a rapid bactericidal effect by interacting with lipopolysaccharide (LPS) or lipoteichoic acid (LTA) and penetrating the bacterial cell membrane. In conclusion, we designed and synthesized a new class of MDLs with potent antimicrobial activity, high proteolytic stability, and low hemolytic activity through N-terminal fatty acid conjugation. Full article
Show Figures

Graphical abstract

10 pages, 1530 KiB  
Article
A Common Polymorphism in RNASE6 Impacts Its Antimicrobial Activity toward Uropathogenic Escherichia coli
by Raul Anguita, Guillem Prats-Ejarque, Mohammed Moussaoui, Brian Becknell and Ester Boix
Int. J. Mol. Sci. 2024, 25(1), 604; https://doi.org/10.3390/ijms25010604 - 3 Jan 2024
Cited by 1 | Viewed by 1386
Abstract
Human Ribonuclease (RNase) 6 is a monocyte and macrophage-derived protein with potent antimicrobial activity toward uropathogenic bacteria. The RNASE6 gene is heterogeneous in humans due to the presence of single nucleotide polymorphisms (SNPs). RNASE6 rs1045922 is the most common non-synonymous SNP, resulting in [...] Read more.
Human Ribonuclease (RNase) 6 is a monocyte and macrophage-derived protein with potent antimicrobial activity toward uropathogenic bacteria. The RNASE6 gene is heterogeneous in humans due to the presence of single nucleotide polymorphisms (SNPs). RNASE6 rs1045922 is the most common non-synonymous SNP, resulting in a G to A substitution that determines an arginine (R) to glutamine (Q) transversion at position 66 in the protein sequence. By structural analysis we observed that R66Q substitution significantly reduces the positive electrostatic charge at the protein surface. Here, we generated both recombinant RNase 6-R66 and -Q66 protein variants and determined their antimicrobial activity toward uropathogenic Escherichia coli (UPEC), the most common cause of UTI. We found that the R66 variant, encoded by the major SNP rs1045922 allele, exhibited superior bactericidal activity in comparison to the Q66 variant. The higher bactericidal activity of R66 variant correlated with an increase in the protein lipopolysaccharide binding and bacterial agglutination abilities, while retaining the same enzymatic efficiency. These findings encourage further work to evaluate RNASE6 SNP distribution and its impact in UTI susceptibility. Full article
Show Figures

Figure 1

16 pages, 2517 KiB  
Article
Novel Antimicrobial Peptides from Saline Environments Active against E. faecalis and S. aureus: Identification, Characterisation and Potential Usage
by Jakub Lach, Magdalena Krupińska, Aleksandra Mikołajczyk, Dominik Strapagiel, Paweł Stączek and Agnieszka Matera-Witkiewicz
Int. J. Mol. Sci. 2023, 24(14), 11787; https://doi.org/10.3390/ijms241411787 - 22 Jul 2023
Cited by 1 | Viewed by 1678
Abstract
Microorganisms inhabiting saline environments have been known for decades as producers of many valuable bioproducts. These substances include antimicrobial peptides (AMPs), the most recognizable of which are halocins produced by halophilic Archaea. As agents with a different modes of action from that of [...] Read more.
Microorganisms inhabiting saline environments have been known for decades as producers of many valuable bioproducts. These substances include antimicrobial peptides (AMPs), the most recognizable of which are halocins produced by halophilic Archaea. As agents with a different modes of action from that of most conventionally used antibiotics, usually associated with an increase in the permeability of the cell membrane as a result of a formation of channels and pores, AMPs are a currently promising object of research focused on the investigation of antibiotics with non-standard modes of action. The aim of this study was to investigate antimicrobial activity against multidrug-resistant human pathogens of three peptides, which were synthetised based on sequences identified in metagenomes from saline environments. The investigations were performed against Enterococcus faecalis, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa, Escherichia coli and Candida albicans. Subsequently, the cytotoxicity and haemolytic properties of the tested peptides were verified. An in silico analysis of the interaction of the tested peptides with molecular targets for reference antibiotics was also carried out in order to verify whether or not they can act in a similar way. The P1 peptide manifested the growth inhibition of E. faecalis at a MIC50 of 32 µg/mL and the P3 peptide at a MIC50 of 32 µg/mL was shown to inhibit the growth of both E. faecalis and S. aureus. Furthermore, the P1 and P3 peptides were shown to have no cytotoxic or haemolytic activity against human cells. Full article
Show Figures

Figure 1

Back to TopTop