Lantibiotics

Information about Lantibiotics

Lantibiotics are a class of peptide antibiotics that contain polycyclic thioether amino acids as well as the unsaturated amino acids dehydroalanine and 2-aminoisobutyric acid. These characteristic cyclic thioether amino acids are composed of either lanthionine or methyllanthionine. Lantibiotics are produced by a large number of Gram positive bacteria such as Streptococcus and Streptomyces to attack other gram positive bacteria and as such they are considered a member of the bacteriocins.

History

^[1]The name Lantibiotics was introduced in 1988 as an abbreviation for "Lanthionine-containing peptide antibiotics". The first structures of these antimicrobial agents were produced by pioneering work by Gross and Morell in the late sixties and early seventies, thus marking the formal introduction of Lantibiotics. Since then Lantibiotics such as Nisin have been used auspiciously for food preservation and have yet to encounter significant bacterial resistance. These attributes of lantibiotics have lead to more detailed research into their structures and biosynthetic pathways.

Classification

Type A Lantibiotics are long flexible molecules - eg Nisin, subtilin, epidermin. Subgroup AI includes Mutacin II, subgroup AII includes Mutacin I & III.
Type B Lantibiotics are globular - eg mersacidin, actagardine, cinnamycin.

Biosynthesis

The biosynthesis is interesting <details to be added>. They are synthesised with a leader polypeptide sequence which is only removed during the transport of the molecule out of the synthesising cell.

Mechanism of action

Lantibiotics show substantial specificity for some components (eg lipid II) of bacterial cell membranes especially of Gram positive bacteria. Type A kill rapidly by pore formation, type B inhibit peptidoglycan biosynthesis. See Brotz and Sahl. JAC (2000) 46, 1-6 for discussion of mechanism of action. They are active in very low concentrations.

Application

^[2]Lantibiotics are produced by Gram-positive bacteria and show strong antimicrobial action towards a wide range of other Gram-positive bacteria. As such they have become attractive candidates for use in food preservation (by inhibiting pathogens that cause food spoilage) and the pharmaceutical industry (to prevent or fight infections in humans or animals). See C. van Kraaij et al, Nat. Prod. Rep. (1999), 16, 583 - 584 for more detailed disccusion of the pharmaceutical application of lantibiotics.

References

1. ^ [1]
2. ^ [2]

1. W. van der Donk et al. Chem. Rev. (2005) 105, 633 - 683
2. C. van Kraaij et al, Nat. Prod. Rep. (1999), 16, 575 - 587.

External links

Peptides (from the Greek πεπτίδια, "small digestibles") are short polymers formed from the linking, in a defined order, of α-amino acids.
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antibiotic is a chemotherapeutic agent that inhibits or abolishes the growth of micro-organisms, such as bacteria, fungi, or protozoans. The term originally referred to any agent with biological activity against living organisms; however, "antibiotic" now is used to refer to
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A thioether (similar to sulfide) is a functional group in organic chemistry that has the structure R¹-S-R² as shown on right. Like many other sulfur-containing compounds, volatile thioethers characteristically have foul odors.
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amino acid is a molecule that contains both amine and carboxyl functional groups. In biochemistry, this term refers to alpha-amino acids with the general formula H₂NCHRCOOH, where R is an organic substituent.
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In chemistry, saturation has four different meanings:

In physical chemistry, saturation is the point at which a solution of a substance can dissolve no more of that substance and additional amounts of that substance will appear as a precipitate.

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Dehydroalanine (or (alpha)-(beta)-di-dehydroalanine) is an uncommon amino acid found in peptides of microbial origin (an unsaturated amino acid).

Many dehydroalanine-containing peptides are toxic or antibiotic. They are a part of lantibiotics or microcystins.
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For other uses, see AIB.

2-Aminoisobutyric acid, or α-aminoisobutyric acid (AIB) or α-methylalanine or 2-methylalanine, is an amino acid with the structural formula is H₂N-C(CH₃)
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For the shiitake flavor compound, see .

Lanthionine is a nonproteinogenic amino acid with the chemical formula (HOOC-CH(NH₂)-CH₂-S-CH₂-CH(NH₂)-COOH).
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Gram-positive bacteria are those that retain a crystal violet dye during the Gram stain process.^[1] Gram-positive bacteria appear blue or violet under a microscope, while Gram-negative bacteria appear red or pink.
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Streptococcus
Rosenbach, 1884

Streptococcus is a genus of spherical Gram-positive bacteria, belonging to the phylum Firmicutes^[1] and the lactic acid bacteria group.
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Streptomyces
Waksman & Henrici 1943

Species

S. ambofaciens
S. achromogenes
S. avermitilis
S. coelicolor
S. clavuligerus
S. felleus
S. ferralitis
S.
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Bacteriocins are proteinaceous toxins produced by bacteria to inhibit the growth of similar or closely related bacterial strain(s). They are phenomenologically analogous to yeast and paramecium killing factors, and are structurally, functionally, and ecologically diverse.
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An antimicrobial is a substance that kills or inhibits the growth of microbes such as bacteria (antibacterial activity), fungi (antifungal activity), viruses (antiviral activity), or parasites (anti-parasitic activity).
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Nisin is a polycyclic peptide antibacterial with 34 amino acid residues used as a food preservative. It contains the uncommon amino acids lanthionine (Lan), methyllanthionine (MeLan), didehydroalanine (Dha) and didehydroaminobutyric acid (Dhb).
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Biosynthesis is a phenomenon where chemical compounds are produced from simpler reagents. Biosynthesis, unlike chemical synthesis, takes place within living organisms and is generally catalysed by enzymes. The process is a vital part of metabolism.
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Food preservation is the process of treating and handling food in such a way as to stop or greatly slow down spoilage to prevent foodborne illness while maintaining nutritional value, density, texture and flavor.
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Enzyme inhibitors are molecules that bind to enzymes and decrease their activity. Since blocking an enzyme's activity can kill a pathogen or correct a metabolic imbalance, many drugs are enzyme inhibitors. They are also used as herbicides and pesticides.
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A pathogen or infectious agent is a biological agent that causes disease or illness to its host.^[1] The term is most often used for agents that disrupt the normal physiology of a multicellular animal or plant.
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A pharmaceutical company, or drug company, is a commercial business whose focus is to research, develop, market and/or distribute drugs, most commonly in the context of healthcare. They can deal in generic and/or brand medications.
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