Peptide Knowledge Center
Advances in Bacterial Lantibiotics
Lantibiotics is a class of antimicrobial peptides, or thioether antibiotics produced by bacteria that are synthesized by the ribosomal pathway and has a special organic group. Lantibiotics is pro- duced by Gram-positive bacteria, and can significantly inhibit the growth of microorganisms, especially Gram-positive bacteria. Excessive use of traditional antibiotics leads to the widespread occurrence of pathogen resistance, lantibiotics has great potential for changing this situation. This study is based on the mechanism of action and product development of lantibiotics, to introduce the introduction, classification, mechanism of action, industrialization process and future pros- pects of lantibiotics one by one.
Antimicrobial peptides are a kind of bioactive small molecular polypeptides induced by organisms, with molecular weight between 3 and 5 kDa and with thermal stability and broad-spectrum antibacterial properties ，Lantibiotics. are a new class of antimicrobial peptides acting on cell membranes. These antibiotics have been discovered, understood and developed recently. At present, lantibiotics are all produced by gram-positive bacteria, which have an inhibitory effect on the positive bacteria and have no effect on the negative bacteri
In 1928 Rogers reported that metabolites of lactic acid bacteria can inhibit the growth of lactobacillus and other streptococci, and the metabolite was later identified as Nisin, It was the first reported that lanthionine was contained in the structure, and was subsequently successfully isolated from lactobacillus by Mattick and Hirsch in 1947.
Hirsch first used Nisin as a food preservative in 1951 to suppress food spoilage caused by Bacillus thuringiensis, and it is still the most successful lantibiotics in the world.
The structural characteristics of lantibiotics
The most distinctive feature of lantibiotics from other antibiotics is that they contain lanthionine and β -methyl lanthionine, etc a rare amino acid.with dicarboxylic acid. These rare amino acids covalently bond to form inner rings in the structure of lantibiotics, which makes lantibiotics have better stability.
The classification of lantibiotics
According to the differences in molecular structure and antibacterial activity of lantibiotics ,Jung suggested classifying them into A and B. Class A is A linear spiral structure with A positive charge and amphiphilicity, which can form holes in the cell membrane and cause cell death. Class B is spherical with negative or no charge, which can inhibit the formation of cell walls.The classification of lantibiotics also includes a special member - the AB two-component lantibiotics Lacticin 3147.The antibiotic is composed of two different polypeptides, which have the characteristics of both A and B.
The sterilization mechanism of lantibiotics
The mechanism of action of class A lantibiotics can be divided into two ways: inhibiting cell wall synthesis and punching holes in the cell membrane. Inhibition of cell wall synthesis mainly involves binding to lipid II, A carrier that transports peptidoglycan during cell wall synthesis, thus preventing cell wall biosynthesis and leading to bacterial death. The perforation on cell membrane is caused by the n-terminal binding of lantibiotics to lipid II, leading to the change of its structure. The C-terminal is inserted into the cell membrane to form a pore, which causes a large amount of cell fluid (potassium, glutamate and ATP) to flow out of the cell and cause cell death.
Industrialization process and future prospect of lantibiotics
Current research shows that virtually all conventional antibiotics (ampicillin, kanamycin, splendomycin, etc.) produce Pathogenic strains that are resistant to them to some extent, so the search for new antibiotics that are less resistant to them is urgent. Lantibiotics have a wide variety of types, broad antibacterial spectrum and high activity, and are not easy to develop cross-resistance, so it is believed that they will be used in the production of biogenic pesticides and medicine and will have a broad prospect and development space. Although current studies have basically revealed the huge research and development potential of lantibiotics, there are few commercial lantibiotics in the world, and Nisin is still one of the most successful cases. The application of lantibiotics in agriculture is mainly reflected in the genetic engineering modification of the existing disease-resistant so that the modified excellent varieties have the resistance to a variety of plant diseases and pathogens. lantibiotics are mainly used as food preservatives in daily life. For example, streptococcus lactis can successfully inhibit the infection of listeria in food, with high stability and safety，in addition, streptococcus lactis can also be used as a health care product to freshen breath. Compared with their role in agricultural bacterial diseases and food preservatives, lantibiotics are still in their infancy in medicine.
The discovery and development of new lantibiotics has been a great success in the era of modern genomics and proteomics, which used to isolate naturally occurring lantibiotics from microorganisms.It is not only from bacterial genomes that new lantibiotics can be predicted, And it can modify the genes and chemical structures that code for lantibiotics to meet the needs of reality, In the next few years, people will be able to actively design new lantibiotics, which will be widely used in agricultural production, food, medicine and more industries, benefiting human beings.
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