After the Swedish scientist Boman et al. isolated Cecropin antimicrobial peptides A and B, people began to have a new understanding of antimicrobial peptides. Insect antimicrobial peptides (AMPs) are natural polypeptides extracted from insect hemolymph, with small molecular weight, stable physical and chemical properties, not easy to be hydrolyzed by digestive enzymes, and difficult to produce drug resistance, and are an important part of the natural immune system. . Research on insect antimicrobial peptides has found that it has a series of advantages that commonly used tumor therapies do not have. Research on insect antimicrobial peptides has found that it has a series of advantages that conventional tumor therapies do not have. Experts have turned their attention to antimicrobial peptides, this unique insect antibacterial Peptide resources have received extensive attention, and the research content focuses on the classification method, structural characteristics, biological activity test, anti-tumor mechanism, and prospect of insect antimicrobial peptides.

Classification and structural characteristics of insect antimicrobial peptides

After insects are immune-stimulated, the hemolymph can produce antibacterial and antitumor activity polypeptides-antibacterial peptides. Some studies have found the existence of antimicrobial peptides in Lepidoptera, Hymenoptera, Isoptera and other insects. According to the difference in structure and function, they can be divided into four categories: cecropin-type antimicrobial peptides, insect defensin-type antimicrobial peptides, proline-rich antimicrobial peptides, and glycine-rich antimicrobial peptides. Cecropin antibacterial peptides contain two amphiphilic α-helix structures in the molecule, do not contain cysteine, and have a molecular weight of about 4 kDa, which can act on Gram-negative bacteria and Gram-positive bacteria. Defensin antimicrobial peptides, with α-helix structure and β-sheet structure, molecular weight of 4 kDa, have antibacterial activity against Gram-positive bacteria. Proline-rich antimicrobial peptides can be divided into two families, namely short-chain (less than 20 amino acids) and long-chain (more than 20 amino acids), consisting of 15-34 amino acids, with a molecular weight of 2-4 kDa, Only acts on Gram-negative bacteria. At present, proline-rich antimicrobial peptides have been extracted from Lepidoptera, Diptera, Hemiptera and Hymenoptera. Glycine-rich antimicrobial peptides are rich in glycine in their primary structures, with a molecular weight of 10–30 kDa, and can have antibacterial effects on Gram-negative bacteria.

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