The Hirudo Medicinalis Microbiome Is a Source of New Antimicrobial Peptides

Antimicrobial peptides (AMPs) are considered a promising new class of anti-infectious agents. This study reports new antimicrobial peptides derived from the Hirudo medicinalis microbiome identified by a computational analysis method applied to the H. medicinalis metagenome. The identified AMPs possess a strong antimicrobial activity against Gram-positive and Gram-negative bacteria (MIC range: 5.3 to 22.4 μM), including Staphylococcus haemolyticus, an opportunistic coagulase–negative pathogen. The secondary structure analysis of peptides via CD spectroscopy showed that all the AMPs except pept_352 have mostly disordered structures that do not change under different conditions. For peptide pept_352, the α–helical content increases in the membrane environment. The examination of the mechanism of action of peptides suggests that peptide pept_352 exhibits a direct membranolytic activity. Furthermore, the cytotoxicity assay demonstrated that the nontoxic peptide pept_1545 is a promising candidate for drug development. Overall, the analysis method implemented in the study may serve as an effective tool for the identification of new AMPs.

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BeStSel: From Secondary Structure Analysis to Protein Fold Prediction by Circular Dichroism Spectroscopy

Methods in Molecular Biology - Structural Genomics ◽

10.1007/978-1-0716-0892-0_11 ◽

2020 ◽

pp. 175-189

Author(s):

András Micsonai ◽

Éva Bulyáki ◽

József Kardos

Keyword(s):

Circular Dichroism ◽

Secondary Structure ◽

Classical Method ◽

Cd Spectroscopy ◽

Protein Fold ◽

Cd Spectra ◽

Secondary Structure Analysis ◽

Β Sheets ◽

Α Helix ◽

Circular Dichroïsm

Abstract Far-UV circular dichroism (CD) spectroscopy is a classical method for the study of the secondary structure of polypeptides in solution. It has been the general view that the α-helix content can be estimated accurately from the CD spectra. However, the technique was less reliable to estimate the β-sheet contents as a consequence of the structural variety of the β-sheets, which is reflected in a large spectral diversity of the CD spectra of proteins containing this secondary structure component. By taking into account the parallel or antiparallel orientation and the twist of the β-sheets, the Beta Structure Selection (BeStSel) method provides an improved β-structure determination and its performance is more accurate for any of the secondary structure types compared to previous CD spectrum analysis algorithms. Moreover, BeStSel provides extra information on the orientation and twist of the β-sheets which is sufficient for the prediction of the protein fold. The advantage of CD spectroscopy is that it is a fast and inexpensive technique with easy data processing which can be used in a wide protein concentration range and under various buffer conditions. It is especially useful when the atomic resolution structure is not available, such as the case of protein aggregates, membrane proteins or natively disordered chains, for studying conformational transitions, testing the effect of the environmental conditions on the protein structure, for verifying the correct fold of recombinant proteins in every scientific fields working on proteins from basic protein science to biotechnology and pharmaceutical industry. Here, we provide a brief step-by-step guide to record the CD spectra of proteins and their analysis with the BeStSel method.

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Molten globule state of human placental cystatin (HPC) at low pH conditions and the effects of trifluoroethanol (TFE) and methanol

Biochemistry and Cell Biology ◽

10.1139/o05-171 ◽

2006 ◽

Vol 84 (2) ◽

pp. 126-134 ◽

Cited By ~ 3

Author(s):

Fouzia Rashid ◽

Sandeep Sharma ◽

M A Baig ◽

Bilqees Bano

Keyword(s):

Conformational Changes ◽

Tertiary Structure ◽

Molten Globule ◽

Structural Features ◽

Cd Spectroscopy ◽

Native State ◽

Molten Globule State ◽

Fluorescence Measurements ◽

Helical Content ◽

Human Placental Cystatin

Acid-induced conformational changes were studied in human placental cystatin (HPC) in terms of circular dichroism (CD) spectroscopy, the binding of hydrophobic dye 1-anilinonapthalene-8-sulphonic acid (ANS), and intrinsic fluorescence measurements. Our results show the formation of an acid-induced molten globule state at pH 2.0, with significant secondary and tertiary interactions that resemble the native state, exposed hydrophobic regions and the effects of trifluoroethanol (TFE) and methanol in conversion of the acid-denatured state of HPC to the alcohol-induced state, which is characterized by increased helical content, disrupted tertiary structure, and the absence of hydrophobic clusters. Alcohol-induced formation of α-helical structures at pH 2.0 is evident from the increase in the ellipticity values at 222 nm, with native-like secondary structural features at 40% TFE. The increase in helical content was observed up to 80% TFE concentration. The ability of TFE (40%) to refold acid-denatured HPC to native-state conformation is also supported by intrinsic and ANS fluorescence measurements.Key words: human placental cystatin, molten globule, acid-induced state, trifluoroethanol, methanol, CD spectroscopy, ANS fluorescence, pH, protein folding.

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Therapeutic antimicrobial peptides may compromise natural immunity

Biology Letters ◽

10.1098/rsbl.2011.1203 ◽

2012 ◽

Vol 8 (3) ◽

pp. 416-418 ◽

Cited By ~ 74

Author(s):

Michelle G. J. L. Habets ◽

Michael A. Brockhurst

Keyword(s):

Antimicrobial Peptides ◽

Therapeutic Use ◽

Innate Immune ◽

Cross Resistance ◽

Drug Candidate ◽

Natural Immunity ◽

New Class ◽

Compensatory Adaptation ◽

Microbial Infections ◽

Potential Risks

Antimicrobial peptides (AMPs) have been proposed as a promising new class of antimicrobials despite warnings that therapeutic use could drive the evolution of pathogens resistant to our own immunity peptides. Using experimental evolution, we demonstrate that Staphylococcus aureus rapidly evolved resistance to pexiganan, a drug-candidate for diabetic leg ulcer infections. Evolved resistance was costly in terms of impaired growth rate, but costs-of-resistance were completely ameliorated by compensatory adaptation. Crucially, we show that, in some populations, experimentally evolved resistance to pexiganan provided S. aureus with cross-resistance to human-neutrophil-defensin-1, a key component of the innate immune response to infection. This unintended consequence of therapeutic use could drastically undermine our innate immune system's ability to control and clear microbial infections. Our results therefore highlight grave potential risks of AMP therapies, with implications for their development.

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Unravelling the antimicrobial activity of peptide hydrogel systems: Current and future perspectives

Soft Matter ◽

10.1039/d1sm00839k ◽

2021 ◽

Author(s):

Emily Cross ◽

Sophie M Coulter ◽

Sreekanth Pentlavalli ◽

Garry Laverty

Keyword(s):

Drug Delivery ◽

Antimicrobial Activity ◽

Antimicrobial Peptides ◽

Future Perspectives ◽

New Class ◽

Significant Interest ◽

Peptide Hydrogel

The use of hydrogels has garnered significant interest as biomaterial and drug delivery platforms for anti-infective applications. For decades antimicrobial peptides have been heralded as a much needed new class...

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Limnonectins: A new class of antimicrobial peptides from the skin secretion of the Fujian large-headed frog (Limnonectes fujianensis)

Biochimie ◽

10.1016/j.biochi.2011.03.003 ◽

2011 ◽

Vol 93 (6) ◽

pp. 981-987 ◽

Cited By ~ 13

Author(s):

Youjia Wu ◽

Lei Wang ◽

Mei Zhou ◽

Chengbang Ma ◽

Xiaole Chen ◽

...

Keyword(s):

Antimicrobial Peptides ◽

Skin Secretion ◽

New Class

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Destabilization of α-Helical Structure in Solution Improves Bactericidal Activity of Antimicrobial Peptides: Opposite Effects on Bacterial and Viral Targets

Antimicrobial Agents and Chemotherapy ◽

10.1128/aac.02146-15 ◽

2016 ◽

Vol 60 (4) ◽

pp. 1984-1991 ◽

Cited By ~ 10

Author(s):

David O. Ulaeto ◽

Christopher J. Morris ◽

Marc A. Fox ◽

Mark Gumbleton ◽

Konrad Beck

Keyword(s):

Ionic Strength ◽

Antimicrobial Peptides ◽

Bactericidal Activity ◽

High Ionic Strength ◽

Gram Negative Bacteria ◽

Gram Negative ◽

Polysorbate 20 ◽

Helical Content ◽

Bactericidal Activities ◽

Structure In Solution

ABSTRACTWe have previously examined the mechanism of antimicrobial peptides on the outer membrane of vaccinia virus. We show here that the formulation of peptides LL37 and magainin-2B amide in polysorbate 20 (Tween 20) results in greater reductions in virus titer than formulation without detergent, and the effect is replicated by substitution of polysorbate 20 with high-ionic-strength buffer. In contrast, formulation with polysorbate 20 or high-ionic-strength buffer has the opposite effect on bactericidal activity of both peptides, resulting in lesser reductions in titer for both Gram-positive and Gram-negative bacteria. Circular dichroism spectroscopy shows that the differential action of polysorbate 20 and salt on the virucidal and bactericidal activities correlates with the α-helical content of peptide secondary structure in solution, suggesting that the virucidal and bactericidal activities are mediated through distinct mechanisms. The correlation of a defined structural feature with differential activity against a host-derived viral membrane and the membranes of both Gram-positive and Gram-negative bacteria suggests that the overall helical content in solution under physiological conditions is an important feature for consideration in the design and development of candidate peptide-based antimicrobial compounds.

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Antimicrobial peptides from Capsicum chinense fruits: agronomic alternatives against phytopathogenic fungi

Bioscience Reports ◽

10.1042/bsr20200950 ◽

2020 ◽

Vol 40 (8) ◽

Author(s):

Layrana de Azevedo dos Santos ◽

Gabriel Bonan Taveira ◽

Marciele Souza da Silva ◽

Rodrigo da Silva Gebara ◽

Lídia da Silva Pereira ◽

...

Keyword(s):

Antimicrobial Activity ◽

Antimicrobial Peptides ◽

High Performance ◽

Protein Extraction ◽

Phytopathogenic Fungi ◽

Lipid Transfer ◽

Capsicum Chinense ◽

Microbial Inhibition ◽

Specific Lipid ◽

Strong Antimicrobial Activity

Abstract In recent years, the antimicrobial activity of peptides isolated from a wide variety of organs from plant species has been reported. However, a few studies have investigated the potential of antimicrobial peptides (AMPs) found in fruits, especially Capsicum chinense (pepper). The present study aimed to purify and characterize peptides from Capsicum chinense fruits and evaluate their inhibitory activities against different phytopathogenic fungi and also analyze the possible mechanisms of action involved in microbial inhibition. After fruit protein extraction and high-performance liquid chromatography (HPLC), different fractions were obtained, named F1 to F10. Peptides in the F4 and F5 fractions were sequenced and revealed similarity with the plant antimicrobial peptides like non-specific lipid transfer proteins and defensin-like peptide. The F4 and F5 fractions presented strong antimicrobial activity against the fungus Fusarium solani and Fusarium oxysporum, causing toxic effects on these fungi, leading to membrane permeabilization, endogenous reactive oxygen species increase, activation of metacaspase and loss of mitochondrial function.

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The Design and Construction of K11: A Novelα-Helical Antimicrobial Peptide

International Journal of Microbiology ◽

10.1155/2012/764834 ◽

2012 ◽

Vol 2012 ◽

pp. 1-6 ◽

Cited By ~ 6

Author(s):

Huang Jin-Jiang ◽

Lu Jin-Chun ◽

Lu Min ◽

Huang Qing-Shan ◽

Li Guo-Dong

Keyword(s):

Pseudomonas Aeruginosa ◽

Antimicrobial Peptides ◽

Antimicrobial Peptide ◽

Broad Spectrum ◽

Staphylococcus Epidermidis ◽

Therapeutic Index ◽

Klebsiella Pneumonia ◽

Gram Negative Bacteria ◽

Drug Resistant ◽

Promising Candidate

Amphipathicα-helical antimicrobial peptides comprise a class of broad-spectrum agents that are used against pathogens. We designed a series of antimicrobial peptides, CP-P (KWKSFIKKLTSKFLHLAKKF) and its derivatives, and determined their minimum inhibitory concentrations (MICs) againstPseudomonas aeruginosa, their minimum hemolytic concentrations (MHCs) for human erythrocytes, and the Therapeutic Index (MHC/MIC ratio). We selected the derivative peptide K11, which had the highest therapeutic index (320) among the tested peptides, to determine the MICs against Gram-positive and Gram-negative bacteria and 22 clinical isolates includingAcinetobacter baumannii, methicillin-resistantStaphylococcus aureus, Pseudomonas aeruginosa, Staphylococcus epidermidis,andKlebsiella pneumonia. K11 exhibited low MICs (less than 10 μg/mL) and broad-spectrum antimicrobial activity, especially against clinically isolated drug-resistant pathogens. Therefore, these results indicate that K11 is a promising candidate antimicrobial peptide for further studies.

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Antimicrobial Peptides: Phylogenic Sources and Biological Activities. First of Two Parts

Current Pharmaceutical Design ◽

10.2174/1381612824666180403123736 ◽

2018 ◽

Vol 24 (10) ◽

pp. 1043-1053 ◽

Cited By ~ 3

Author(s):

Thea Magrone ◽

Matteo Antonio Russo ◽

Emilio Jirillo

Keyword(s):

Antimicrobial Peptides ◽

Biological Activities ◽

Cell Types ◽

Human Pathogens ◽

New Class ◽

Novel Drugs ◽

Broad Variety ◽

Living Organisms ◽

Self Protection

Antimicrobial peptides (AMPs) are phylogenetically ancient substances released by living organisms for self protection against a broad variety of microbes. Moreover, AMPs are endowed with immune modulatory activities, linking innate and adaptive immunity together. Lantibiotics are AMPs of bacterial origin currently investigated for the generation of a new class of anti-infective compounds, owing to the phenomenon of antibiotic resistance against a broad variety of bacteria. Also, plants and marine AMPs are screened as novel drugs against human pathogens. Human AMPs encompass defensins and cathelicidins produced by various cell types mostly at mucosal sites. Besides their antimicrobial activity, both AMPs have been shown to trigger either inflammatory or anti-inflammatory pathways. Food-derived AMPs are mostly represented by lactoferrin and lysozyme both present in secretions, e.g., milk, and appear to be very exploitable for the generation of functional foods. Finally, the role of natural products ingested with food or administered as supplements on induction and production of AMPs will be discussed.

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