Multimodal binding and inhibition of bacterial ribosomes by the antimicrobial peptides Api137 and Api88.

Proline-rich antimicrobial peptides (PrAMPs) inhibit bacterial protein biosynthesis by binding to the polypeptide exit tunnel (PET) near the peptidyl transferase center. Api137, an optimized derivative of honeybee PrAMP apidaecin, inhibits protein expression by trapping release factors (RFs), which interact with stop codons on ribosomes to terminate translation. This study uses cryo-EM, functional assays and molecular dynamic (MD) simulations to show that Api137 additionally occupies a second binding site near the exit of the PET and can repress translation independently of RF-trapping. Api88, a C-terminally amidated (-CONH2) analog of Api137 (-COOH), binds to the same sites, occupies a third binding pocket and interferes with the translation process presumably without RF-trapping. In conclusion, apidaecin-derived PrAMPs inhibit bacterial ribosomes by multimodal mechanisms caused by minor structural changes and thus represent a promising pool for drug development efforts.

Antimicrobial Peptides towards Clinical Application-A Long History to Be Concluded.

Antimicrobial peptides (AMPs) are molecules with an amphipathic structure that enables them to interact with bacterial membranes. This interaction can lead to membrane crossing and disruption with pore formation, culminating in cell death. They are produced naturally in various organisms, including humans, animals, plants and microorganisms. In higher animals, they are part of the innate immune system, where they counteract infection by bacteria, fungi, viruses and parasites. AMPs can also be designed de novo by bioinformatic approaches or selected from combinatorial libraries, and then produced by chemical or recombinant procedures. Since their discovery, AMPs have aroused interest as potential antibiotics, although few have reached the market due to stability limits or toxicity. Here, we describe the development phase and a number of clinical trials of antimicrobial peptides. We also provide an update on AMPs in the pharmaceutical industry and an overall view of their therapeutic market. Modifications to peptide structures to improve stability in vivo and bioavailability are also described.

LL37 Microspheres Loaded on Activated Carbon-chitosan Hydrogel: Anti-bacterial and Anti-toxin Wound Dressing for Chronic Wound Infections.

Antimicrobial peptide LL37 is a promising antibacterial candidate due to its potent antimicrobial activity with no known bacterial resistance. However, intrinsically LL37 is susceptible to degradation in wound fluids limits its effectiveness. Bacterial toxins which are released after cell lysis are found to hinder wound healing. To address these challenges, encapsulating LL37 in microspheres (MS) and loading the MS onto activated carbon (AC)-chitosan (CS) hydrogel. This advanced wound dressing not only protects LL37 from degradation but also targets bacterial toxins, aiding in the healing of chronic wound infections. First, LL37 MS and LL37-AC-CS hydrogel were prepared and characterised in terms of physicochemical properties, drug release, and peptide-polymer compatibility. Antibacterial and antibiofilm activity, bacterial toxin elimination, cell migration, and cell cytotoxicity activities were investigated. LL37-AC-CS hydrogel was effective against Escherichia coli, Pseudomonas aeruginosa, and Staphylococcus aureus. LL37-AC-CS hydrogel bound more endotoxin than AC with CS hydrogel alone. The hydrogel also induced cell migration after 72 h and showed no cytotoxicity towards NHDF after 72 h of treatment. In conclusion, the LL37-AC-CS hydrogel was shown to be a stable, non-toxic advanced wound dressing method with enhanced antimicrobial and antitoxin activity, and it can potentially be applied to chronic wound infections to accelerate wound healing.

An Overview of Frog Skin-Derived Esc Peptides: Promising Multifunctional Weapons against Pseudomonas aeruginosa-Induced Pulmonary and Ocular Surface Infections.

Antimicrobial resistance is a silent pandemic harming human health, and Pseudomonas aeruginosa is the most common bacterium responsible for chronic pulmonary and eye infections. Antimicrobial peptides (AMPs) represent promising alternatives to conventional antibiotics. In this review, the in vitro/in vivo activities of the frog skin-derived AMP Esc(1-21) are shown. Esc(1-21) rapidly kills both the planktonic and sessile forms of P. aeruginosa and stimulates migration of epithelial cells, likely favoring repair of damaged tissue. However, to undertake preclinical studies, some drawbacks of AMPs (cytotoxicity, poor biostability, and limited delivery to the target site) must be overcome. For this purpose, the stereochemistry of two amino acids of Esc(1-21) was changed to obtain the diastereomer Esc(1-21)-1c, which is more stable, less cytotoxic, and more efficient in treating P. aeruginosa-induced lung and cornea infections in mouse models. Incorporation of these peptides (Esc peptides) into nanoparticles or immobilization to a medical device (contact lens) was revealed to be an effective strategy to ameliorate and/or to prolong the peptides' antimicrobial efficacy. Overall, these data make Esc peptides encouraging candidates for novel multifunctional drugs to treat lung pathology especially in patients with cystic fibrosis and eye dysfunctions, characterized by both tissue injury and bacterial infection.

Antibacterial and Hemolytic Activity of Antimicrobial Hydrogels Utilizing Immobilized Antimicrobial Peptides.

Antimicrobial peptides (AMPs) are viewed as potential compounds for the treatment of bacterial infections. Nevertheless, the successful translation of AMPs into clinical applications has been impeded primarily due to their low stability in biological environments and potential toxicological concerns at higher concentrations. The covalent attachment of AMPs to a material's surface has been sought to improve their stability. However, it is still an open question what is required to best perform such an attachment and the role of the support. In this work, six different AMPs were covalently attached to a long-ranged ordered amphiphilic hydrogel, with their antibacterial efficacy evaluated and compared to their performance when free in solution. Among the tested AMPs were four different versions of synthetic end-tagged AMPs where the sequence was altered to change the cationic residue as well as to vary the degree of hydrophobicity. Two previously well-studied AMPs, Piscidin 1 and Omiganan, were also included as comparisons. The antibacterial efficacy against Staphylococcus aureus remained largely consistent between free AMPs and those attached to surfaces. However, the activity pattern against Pseudomonas aeruginosa on hydrogel surfaces displayed a marked contrast to that observed in the solution. Additionally, all the AMPs showed varying degrees of hemolytic activity when in solution. This activity was entirely diminished, and all the AMPs were non-hemolytic when attached to the hydrogels.

Vesicle protrusion induced by antimicrobial peptides suggests common carpet mechanism for short antimicrobial peptides.

Short-cationic alpha-helical antimicrobial peptides (SCHAMPs) are promising candidates to combat the growing global threat of antimicrobial resistance. They are short-sequenced, selective against bacteria, and have rapid action by destroying membranes. A full understanding of their mechanism of action will provide key information to design more potent and selective SCHAMPs. Molecular Dynamics (MD) simulations are invaluable tools that provide detailed insights into the peptide-membrane interaction at the atomic- and meso-scale level. We use atomistic and coarse-grained MD to look into the exact steps that four promising SCHAMPs-BP100, Decoralin, Neurokinin-1, and Temporin L-take when they interact with membranes. Following experimental set-ups, we explored the effects of SCHAMPs on anionic membranes and vesicles at multiple peptide concentrations. Our results showed all four peptides shared similar binding steps, initially binding to the membrane through electrostatic interactions and then flipping on their axes, dehydrating, and inserting their hydrophobic moieties into the membrane core. At higher concentrations, fully alpha-helical peptides induced membrane budding and protrusions. Our results suggest the carpet mode of action is fit for the description of SCHAMPs lysis activity and discuss the importance of large hydrophobic residues in SCHAMPs design and activity.

Antibacterial activity of a short de novo designed peptide against fish bacterial pathogens.

In the face of increasing antimicrobial resistance in aquaculture, researchers are exploring novel substitutes to customary antibiotics. One potential solution is the use of antimicrobial peptides (AMPs). We aimed to design and evaluate a novel, short, and compositionally simple AMP with potent activity against various bacterial pathogens in aquaculture. The resulting peptide, KK12YW, has an amphipathic nature and net charge of + 7. Molecular docking experiments disclosed that KK12YW has a strong affinity for aerolysin, a virulence protein produced by the bacterial pathogen Aeromonas sobria. KK12YW was synthesized using Fmoc chemistry and tested against a range of bacterial pathogens, including A. sobria, A. salmonicida, A. hydrophila, Edwardsiella tarda, Vibrio parahaemolyticus, Pseudomonas aeruginosa, Escherichia coli, Staphylococcus epidermidis, and methicillin-resistant S. aureus. The AMP showed promising antibacterial activity, with MIC and MBC values ranging from 0.89 to 917.1 µgmL-1 and 3.67 to 1100.52 µgmL-1, respectively. In addition, KK12YW exhibited resistance to high temperatures and remained effective even in the presence of serum and salt, indicating its stability. The peptide also demonstrated minimal hemolysis toward fish RBCs, even at higher concentrations. Taken together, these findings indicate that KK12YW could be a highly promising and viable substitute for conventional antibiotics to combat microbial infections in aquaculture.

Broad-spectrum activity of membranolytic cationic macrocyclic peptides against multi-drug resistant bacteria and fungi.

The emergence of multidrug-resistant (MDR) strains causes severe problems in the treatment of microbial infections owing to limited treatment options. Antimicrobial peptides (AMPs) are drawing considerable attention as promising antibiotic alternative candidates to combat MDR bacterial and fungal infections. Herein, we present a series of small amphiphilic membrane-active cyclic peptides composed, in part, of various nongenetically encoded hydrophilic and hydrophobic amino acids. Notably, lead cyclic peptides 3b and 4b showed broad-spectrum activity against drug-resistant Gram-positive (MIC = 1.5-6.2 µg/mL) and Gram-negative (MIC = 12.5-25 µg/mL) bacteria, and fungi (MIC = 3.1-12.5 µg/mL). Furthermore, lead peptides displayed substantial antibiofilm action comparable to standard antibiotics. Hemolysis (HC50 = 230 µg/mL) and cytotoxicity (>70 % cell viability against four different mammalian cells at 100 µg/mL) assay results demonstrated the selective lethal action of 3b against microbes over mammalian cells. A calcein dye leakage experiment substantiated the membranolytic effect of 3b and 4b, which was further confirmed by scanning electron microscopy. The behavior of 3b and 4b in aqueous solution and interaction with phospholipid bilayers were assessed by employing nuclear magnetic resonance (NMR) spectroscopy in conjunction with molecular dynamics (MD) simulations, providing a solid structural basis for understanding their membranolytic action. Moreover, 3b exhibited stability in human blood plasma (t1/2 = 13 h) and demonstrated no signs of resistance development against antibiotic-resistant S. aureus and E. coli. These findings underscore the potential of these newly designed amphiphilic cyclic peptides as promising anti-infective agents, especially against Gram-positive bacteria.

First vertebrate BRICHOS antimicrobial peptides: ß-hairpin host defense peptides in limbless amphibia lung resemble those of marine worms.

Innate immunity of invertebrates offers potent antimicrobial peptides (AMPs) against drug-resistant infections. To identify new worm ß-hairpin AMPs, we explored the sequence diversity of proteins with a BRICHOS domain, which comprises worm AMP precursors. Strikingly, we discovered new BRICHOS AMPs not in worms, but in caecilians, the least studied clade of vertebrates. Two precursor proteins from Microcaecilia unicolor and Rhinatrema bivittatum resemble SP-C lung surfactants and bear worm AMP-like peptides at C-termini. The analysis of M. unicolor tissue transcriptomes shows that the AMP precursor is highly expressed in the lung along with regular SP-C, suggesting a different, protective function. The peptides form right-twisted ß-hairpins, change conformation upon lipid binding, and rapidly disrupt bacterial membranes. Both peptides exhibit broad-spectrum activity against multidrug-resistant ESKAPE pathogens with 1-4 µM MICs and remarkably low toxicity, giving 40-70-fold selectivity towards bacteria. These BRICHOS AMPs, previously unseen in vertebrates, reveal a novel lung innate immunity mechanism and offer a promising antibiotics template.

LL-37: Structures, Antimicrobial Activity, and Influence on Amyloid-Related Diseases.

Antimicrobial peptides (AMPs), as well as host defense peptides (HDPs), constitute the first line of defense as part of the innate immune system. Humans are known to express antimicrobial precursor proteins, which are further processed to generate AMPs, including several types of α/ß defensins, histatins, and cathelicidin-derived AMPs like LL37. The broad-spectrum activity of AMPs is crucial to defend against infections caused by pathogenic bacteria, viruses, fungi, and parasites. The emergence of multi-drug resistant pathogenic bacteria is of global concern for public health. The prospects of targeting antibiotic-resistant strains of bacteria with AMPs are of high significance for developing new generations of antimicrobial agents. The 37-residue long LL37, the only cathelicidin family of AMP in humans, has been the major focus for the past few decades of research. The host defense activity of LL37 is likely underscored by its expression throughout the body, spanning from the epithelial cells of various organs-testis, skin, respiratory tract, and gastrointestinal tract-to immune cells. Remarkably, apart from canonical direct killing of pathogenic organisms, LL37 exerts several other host defense activities, including inflammatory response modulation, chemo-attraction, and wound healing and closure at the infected sites. In addition, LL37 and its derived peptides are bestowed with anti-cancer and anti-amyloidogenic properties. In this review article, we aim to develop integrative, mechanistic insight into LL37 and its derived peptides, based on the known biophysical, structural, and functional studies in recent years. We believe that this review will pave the way for future research on the structures, biochemical and biophysical properties, and design of novel LL37-based molecules.

Dimerization of the ß-Hairpin Membrane-Active Cationic Antimicrobial Peptide Capitellacin from Marine Polychaeta: An NMR Structural and Thermodynamic Study.

Capitellacin is the ß-hairpin membrane-active cationic antimicrobial peptide from the marine polychaeta Capitella teleta. Capitellacin exhibits antibacterial activity, including against drug-resistant strains. To gain insight into the mechanism of capitellacin action, we investigated the structure of the peptide in the membrane-mimicking environment of dodecylphosphocholine (DPC) micelles using high-resolution NMR spectroscopy. In DPC solution, two structural forms of capitellacin were observed: a monomeric ß-hairpin was in equilibrium with a dimer formed by the antiparallel association of the N-terminal ß-strands and stabilized by intermonomer hydrogen bonds and Van der Waals interactions. The thermodynamics of the enthalpy-driven dimerization process was studied by varying the temperature and molar ratios of the peptide to detergent. Cooling the peptide/detergent system promoted capitellacin dimerization. Paramagnetic relaxation enhancement induced by lipid-soluble 12-doxylstearate showed that monomeric and dimeric capitellacin interacted with the surface of the micelle and did not penetrate into the micelle interior, which is consistent with the "carpet" mode of membrane activity. An analysis of the known structures of ß-hairpin AMP dimers showed that their dimerization in a membrane-like environment occurs through the association of polar or weakly hydrophobic surfaces. A comparative analysis of the physicochemical properties of ß-hairpin AMPs revealed that dimer stability and hemolytic activity are positively correlated with surface hydrophobicity. An additional positive correlation was observed between hemolytic activity and AMP charge. The data obtained allowed for the provision of a more accurate description of the mechanism of the oligomerization of ß-structural peptides in biological membranes.

Antimicrobial peptides designed by computational analysis of proteomes.

Antimicrobial peptides (AMPs) are promising cationic and amphipathic molecules to fight antibiotic resistance. To search for novel AMPs, we applied a computational strategy to identify peptide sequences within the organisms' proteome, including in-house developed software and artificial intelligence tools. After analyzing 150.450 proteins from eight proteomes of bacteria, plants, a protist, and a nematode, nine peptides were selected and modified to increase their antimicrobial potential. The 18 resulting peptides were validated by bioassays with four pathogenic bacterial species, one yeast species, and two cancer cell-lines. Fourteen of the 18 tested peptides were antimicrobial, with minimum inhibitory concentrations (MICs) values under 10 µM against at least three bacterial species; seven were active against Candida albicans with MICs values under 10 µM; six had a therapeutic index above 20; two peptides were active against A549 cells, and eight were active against MCF-7 cells under 30 µM. This study's most active antimicrobial peptides damage the bacterial cell membrane, including grooves, dents, membrane wrinkling, cell destruction, and leakage of cytoplasmic material. The results confirm that the proposed approach, which uses bioinformatic tools and rational modifications, is highly efficient and allows the discovery, with high accuracy, of potent AMPs encrypted in proteins.

Structure modification of anoplin for fighting resistant bacteria.

The emergence of bacterial resistance has posed a significant challenge to clinical antimicrobial treatment, rendering commonly used antibiotics ineffective. The development of novel antimicrobial agents and strategies is imperative for the treatment of resistant bacterial infections. Antimicrobial peptides (AMPs) are considered a promising class of antimicrobial agents due to their low propensity for resistance and broad-spectrum activity. Anoplin is a small linear α-helical natural antimicrobial peptide that was isolated from the venom of the solitary wasp Anplius samariensis. It exhibits rich biological activity, particularly broad-spectrum antimicrobial activity and low hemolytic activity. Over the past three decades, more than 40 research publications on anoplin have been made available online. This review focuses on the advancements of anoplin in antimicrobial research, encompassing its sources, characterization, antimicrobial activity, influencing factors and structural modifications. The aim is to provide assistances for the development of new antimicrobial agents that can combat bacterial resistance.

Combating Antimicrobial Resistance by Employing Antimicrobial Peptides: Immunomodulators and Therapeutic Agents against Infectious Diseases.

The rising prevalence of multiple-drug-resistant pathogens poses a formidable challenge to conventional antimicrobial treatments. The inability of potent antibiotics to combat these "superbugs" underscores the pressing need for alternative therapeutic agents. Antimicrobial peptides (AMPs) represent an alternative class of antibiotics. AMPs are essential immunomodulatory molecules that are found in various organisms. They play a pivotal role in managing microbial ecosystems and bolstering innate immunity by targeting and eliminating invading microorganisms. AMPs also have applications in the agriculture sector by combating animal as well as plant pathogens. AMPs can be exploited for the targeted therapy of various diseases and can also be used in drug-delivery systems. They can be used in synergy with current treatments like antibiotics and can potentially lead to a lower required dosage. AMPs also have huge potential in wound healing and regenerative medicine. Developing AMP-based strategies with improved safety, specificity, and efficacy is crucial in the battle against alarming global microbial resistance. This review will explore AMPs' increasing applicability, their mode of antimicrobial activity, and various delivery systems enhancing their stability and efficacy.

Hydrocarbon stapled temporin-L analogue as potential antibacterial and antiendotoxin agents with enhanced protease stability.

Antimicrobial resistance (AMR) is a serious global concern and a huge burden on the healthcare system. Antimicrobial peptides (AMPs) are considered as a solution of AMR due to their membrane-lytic and intracellular mode of action and therefore resistance development against AMPs is less frequent. One such AMPs, temporin-L (TL) is a 13-mer peptide reported as a potent and broad-spectrum antibacterial agent with significant immunomodulatory activity. However, TL is toxic to human erythrocytes at their antibacterial concentrations and therefore various analogues were synthesized with potent antimicrobial activity and lower hemolytic activity. In this work, we have selected a non-toxic engineered analogue of TL (eTL) and performed hydrocarbon stapling of amino acid residues at i to i + 4 positions at different part of sequence. The synthesized peptides were investigated against both the gram-positive and gram-negative bacteria as well as methicillin resistant S. aureus, its MIC was measured in the concentrations range of 0.9-15.2 µM. All analogues were found equal or better antibacterial as compared to parent peptide. Interestingly one analogue eTL [5-9] was found to be non-cytotoxic and stable in presence of the human serum. Mode of action studies revealed membrane depolarizing and disruptive mode of action with live MRSA. Further in vivo studies of antimicrobial against MRSA infection and anti-endotoxin activities in mice model revealed potential activity of the stapled peptide analogue. Overall, this reports on stapled analogue of the AMPs highlights an important strategy for the development of new antibacterial therapeutics against AMR.

A Comprehensive Review of Patented Antimicrobial Peptides from Amphibian Anurans.

Since the 1980s, studies of antimicrobial peptides (AMPs) derived from anuran skin secretions have unveiled remarkable structural diversity and a wide range of activities. This study explores the potential of these peptides for drug development by examining granted patents, amino acid modifications related to patented peptides, and recent amphibians' taxonomic updates influencing AMP names. A total of 188 granted patents related to different anuran peptides were found, with Asia and North America being the predominant regions, contributing 65.4% and 15.4%, respectively. Conversely, although the Neotropical region is the world's most diversified region for amphibians, it holds only 3.7% of the identified patents. The antimicrobial activities of the peptides are claimed in 118 of these 188 patents. Additionally, for 160 of these peptides, 66 patents were registered for the natural sequence, 69 for both natural and derivative sequences, and 20 exclusively for sequence derivatives. Notably, common modifications include alterations in the side chains of amino acids and modifications to the peptides' N- and C-termini. This review underscores the biomedical potential of anuran-derived AMPs, emphasizing the need to bridge the gap between AMP description and practical drug development while highlighting the urgency of biodiversity conservation to facilitate biomedical discoveries.

The antibacterial properties of branched peptides based on poly(l-arginine): In vitro antibacterial evaluation and molecular dynamic simulations.

The emergence of bacterial strains resistant to antibiotics is a major issue in the medical field. Antimicrobial peptides are widely studied as they do not generate as much resistant bacterial strains as conventional antibiotics and present a broad range of activity. Among them, the homopolypeptide poly(l-arginine) presents promising antibacterial properties, especially in the perspective of its use in biomaterials. Linear poly(l-arginine) has been extensively studied but the impact of its 3D structure remains unknown. In this study, the antibacterial properties of newly synthesized branched poly(l-arginine) peptides, belonging to the family of multiple antigenic peptides, are evaluated. First, in vitro activities of the peptides shows that branched poly(l-arginine) is more efficient than linear poly(l-arginine) containing the same number of arginine residues. Surprisingly, peptides with more arms and more residues are not the most effective. To better understand these unexpected results, interactions between these peptides and the membranes of Gram positive and Gram negative bacteria are simulated thanks to molecular dynamic. It is observed that the bacterial membrane is more distorted by the branched structure than by the linear one and by peptides containing smaller arms. This mechanism of action is in full agreement with in vitro results and suggest that our simulations form a robust model to evaluate peptide efficiency towards pathogenic bacteria.

Effect of tryptophan position and lysine/arginine substitution in antimicrobial peptides on antifungal action.

Every year, the overprescription, misuse, and improper disposal of antibiotics have led to the rampant development of drug-resistant pathogens and, in turn, a significant increase in the number of patients who die of drug-resistant fungal infections. Recently, researchers have begun investigating the use of antimicrobial peptides (AMPs) as next-generation antifungal agents to inhibit the growth of drug-resistant fungi. The antifungal activity of alpha-helical peptides designed using the cationic amino acids containing lysine and arginine and the hydrophobic amino acids containing isoleucine and tryptophan were evaluated using 10 yeast and mold fungi. Among these peptides, WIK-14, which is composed of a 14-mer with tryptophan sequences at the amino terminus, showed the best antifungal activity via transient pore formation and ROS generation. In addition, the in vivo antifungal effects of WIK-14 were investigated in a mouse model infected with drug-resistant Candida albicans. The results demonstrate the potential of AMPs as antifungal agents.

Rational Design of a Potent Antimicrobial Peptide Based on the Active Region of a Gecko Cathelicidin.

The emergence of multidrug-resistant (MDR) bacteria presents a significant challenge to public health, increasing the risk of infections that are resistant to current antibiotic treatment. Antimicrobial peptides (AMPs) offer a promising alternative to conventional antibiotics in the prevention of MDR bacterial infections. In the present study, we identified a novel cathelicidin AMP from Gekko japonicus, which exhibited broad-spectrum antibacterial activity against both Gram-negative and Gram-positive bacteria, with minimal inhibitory concentrations ranging from 2.34 to 4.69 µg/mL. To improve its potential therapeutic application, a series of peptides was synthesized based on the active region of the gecko-derived cathelicidin. The lead peptide (RH-16) showed an antimicrobial activity comparable to that of the parent peptide. Structural characterization revealed that RH-16 adopted an amphipathic α-helical conformation. Furthermore, RH-16 demonstrated neither hemolytic nor cytotoxic activity but effectively killed a wide range of clinically isolated, drug-resistant bacteria. The antimicrobial activity of RH-16 was attributed to the nonspecific targeting of bacterial membranes, leading to rapid bacterial membrane permeabilization and rupture. RH-16 also retained its antibacterial activity in plasma and exhibited mild toxicity in vivo. Notably, RH-16 offered robust protection against skin infection in a murine model. Therefore, this newly identified cathelicidin AMP may be a strong candidate for future pharmacological development targeting multidrug resistance. The use of a rational design approach for isolating the minimal antimicrobial unit may accelerate the transition of natural AMPs to clinically applicable antibacterial agents.

The amphipathic design in helical antimicrobial peptides.

Amphipathicity is a critical characteristic of helical antimicrobial peptides (AMPs). The hydrophilic region, primarily composed of cationic residues, plays a pivotal role in the initial binding to negatively charged components on bacterial membranes through electrostatic interactions. Subsequently, the hydrophobic region interacts with hydrophobic components, inducing membrane perturbation, ultimately leading to cell death, or inhibiting intracellular function. Due to the extensive diversity of natural and synthetic AMPs with regard to the design of amphipathicity, it is complicated to study the structure-activity relationships. Therefore, this work aims to categorize the common amphipathic design and investigate their impact on the biological properties of AMPs. Besides, the connection between current structural modification approaches and amphipathic styles was also discussed.