Antimicrobial peptide is a kind of antimicrobial peptide found in Bacillus amyloliquefaciens Y2. It has antimicrobial activity.

Background Antimicrobial peptides refer to a variety of peptides with inhibitory or bactericidal activity in vivo, usually containing 20-60 amino acid residues with a molecular weight of 2000-7000 Da. Most of antimicrobial peptides are alkaline as well as with a good thermal stability. Currently, the single drug target, long-term widespread use and drug resistance of antibiotics have hindered their applications in clinical infection management. More and more studies have shown that antimicrobial peptides from synthetic and natural sources have broad-spectrum antibacterial activity, high specificity and low toxicity, and are expected to be the excellent alternatives of antibiotics to overcome drug resistance, thus being widely used in the pharmaceutical field, food industry and agricultural engineering.

Classification of Antimicrobial Peptides Antimicrobial peptides are manifold according to their structural features. Statistics show that the highest percentage of antimicrobial peptides are those containing disulfide bridge structures, followed by those with α-helix and β-fold as well as both structures. However, the structures of a considerable proportion of antimicrobial peptides remain unknown. Among them, α-helical peptides are widely distributed and diverse, with amphiphilic structures in the molecule, and mainly achieve bactericidal effects by changing the permeability and barrier function of the phospholipid bilayer of cell membranes, or by penetrating the membrane interface to destroy the membrane structure. β-folded peptides usually are more structural complex than α-helical antimicrobial peptides, presenting as ring-like molecules with structures of intramolecular disulfide bonds.