Antimicrobial Peptides
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Antimicrobial peptides (AMPs), also called host defense peptides (HDPs), which commonly content 5-40 amino acids, are natural antibiotics produced by various organisms.
Classification of Antimicrobial Peptides
The first AMP was found by Dubos when extracted an antimicrobial agent from a soil bacillus strain in 1939. This extract was demonstrated to protect mice from pneumococci infection. Since then nearly 5,000 AMPs have been found or synthesized. They usually have the common characteristics: small peptide (30–60 aa), strong cationic (pI 8.9–10.7), heat-stable (100℃, 15 min), no drug fastness and no effect on eukaryotic cell. Almost all of them have a positively charged surface. The selective interaction with the membrane of microorganisms generally depends on the cationic nature of AMPs. According to their charge they can be divided into cationic peptides and non-cationic peptides. The largest group corresponds to cationic peptides, which is divided in the following three classes:
- The first category composed by linear cationic α-helical peptides, such as Magainin and Cecropins that are linear before their interaction with the cell membrane, and then adopt an amphipathic α-helical secondary structure.
- The second category comprises cationic peptides enriched for specific amino acids like proline, arginine, and other residues. These peptides are linear, although some may display extended coils.
- The third category includes cationic peptides that contain cysteine residues and form disulphide bonds and stable β-sheets. For example defensins have six cysteine residues and are divided according to the alignment of their disulphide bridges.
Other groups of AMPs are described as non-cationic peptides and are also an important part of the innate immune system.
Mechanism of Action of Antimicrobial Peptides
Currently, several complex and controversial mechanisms of action exist as to how AMPs disrupt the bacterial cell membrane. The four popular models are the carpet model, the toroidal pore model the barrel-stave model and the aggregate model. A growing body of evidence suggested that AMPs had other mechanisms along with membrane penetration and pore formation. (Fig 1).
Fig 1 Models of antibacterial mechanisms of AMPs (Zhang, QY., Yan, ZB., Meng, YM. et al. Military Med Res 8, 48 (2021).)
Most AMPs act by provoking an increase in plasma membrane permeability. First step in the mechanism of membrane permeabilization is the electrostatic interaction between the positively charged AMP with the negatively charged membrane surface of the microorganism. Subsequent disruption of the membrane by creation of pores within the microbial membrane ultimately results in cell death of the organism due to leakage of ions, metabolites, cessation of membrane-coupled respiration, and biosynthesis. The mechanics of AMPs represent an unusual source for the targeted exploration of new applications in the therapy of microbial and viral infection, cancer, and sepsis.
Activity of Antimicrobial Peptides
- Antibacterial Activity
- Antiviral Activity
- Antiparasitic Activity
- Immunomodulatory Activity
- Tumor Modulatory Activity
- Other Activities: AMPs can promote wound healing after skin injury; AMPs are related to the occurrence and development of diabetes; AMPs can regulate NETs and inflammation and are involved in the process of sepsis infection.
Application of Antimicrobial Peptides
AMPs damage microorganisms mostly by membrane disruption, making it difficult for microorganisms to develop resistance and also make itself more popular in pharmacology. Antimicrobial peptides can not induce the production of resistant bacteria, and it also inhibits the production of harmful cytokines induced by bacterial products. Therefore, they can be used to prepare antibacterial and anti-viral drugs. In addition, antimicrobial peptides can also be used as drug carriers.
Antimicrobial peptides can be used as potential alternatives to chemical pesticides. Besides, AMPs have been widely studied for producing transgenic plants resistant to microbial diseases.
Some studies show AMPs as feed additives have remarkable effects compared with the traditional antibiotics.
Antimicrobial peptides have the characteristics of acid resistance, high temperature resistance, thermal stability, etc., and can be used as food preservatives. Unlike chemical preservatives, antimicrobial peptide preservatives are bactericidal, not bacteriostatic.
We offer the many antimicrobial peptides services:
Competitive Advantages
- Highly Customizable: Flexible synthesis scales, various modification types, and diversified delivery forms.
- Technical Support: Professional team provides you with comprehensive pre-sale consultation, order design, and after-sales service to ensure the products deliver smoothly.
- Cost-Effective: Competitive prices and short turnaround time.
Creative Peptides can offer a wide range of AMPs to fully support your project.
