Nevertheless, AMPs are most commonly categorized into four classes based on their secondary structures, i.e., linear α-helical peptides, β-sheet-containing peptides, peptides involving α- and β-elements, and linear extended structures ( 10).

They can also be classified based on their biosynthetic mechanisms, e.g., ribosomal synthesized or nonribosomal synthesized AMPs. AMPs can be grouped according to their source organisms, such as bacteriocins, fungal peptide antibiotics, plant thionins and defensins, insect defensins and cecropins, amphibian magainins and temporins, and defensins from higher vertebrates ( 7, – 9). AMPs have been discovered in most life forms, making their classification a non-trivial task ( 6). Antimicrobial peptides (AMPs) are linear or cyclic peptides consisting of 10 to 100 amino acid residues ( 3, – 5).

It is a global health and economic issue which requires novel antimicrobial drugs with different killing mechanisms ( 2). It has been predicted that, without urgent intervention in controlling resistance, the estimated global deaths resulting from AMR would reach 10 million per year by 2050 and cost the world up to 100 trillion USD ( 1).

The misuse of traditional antibiotics and slow development of new antibiotics has resulted in antimicrobial resistance (AMR).

Free instal Ni Hao, Li Huan Ying