Peptides are short chains of amino acids linked by peptide bonds. A polypeptide is a longer, continuous, unbranched peptide chain. Polypeptides which have a molecular weight of 10000 or more are called proteins. Chains of fewer than twenty amino acids are called oligopeptides, and include dipeptides, tripeptides, and tetrapeptides.
Bacteriocins are proteinaceous or peptidic toxins produced by bacteria to inhibit the growth of similar or closely related bacterial strain(s). They are similar to yeast and paramecium killing factors, and are structurally, functionally, and ecologically diverse. Applications of bacteriocins are being tested to assess their application as narrow-spectrum antibiotics.
Nonribosomal peptides (NRP) are a class of peptide secondary metabolites, usually produced by microorganisms like bacteria and fungi. Nonribosomal peptides are also found in higher organisms, such as nudibranchs, but are thought to be made by bacteria inside these organisms. While there exist a wide range of peptides that are not synthesized by ribosomes, the term nonribosomal peptide typically refers to a very specific set of these as discussed in this article.
Thiazole, or 1,3-thiazole, is a heterocyclic compound that contains both sulfur and nitrogen. The term 'thiazole' also refers to a large family of derivatives. Thiazole itself is a pale yellow liquid with a pyridine-like odor and the molecular formula C3H3NS. The thiazole ring is notable as a component of the vitamin thiamine (B1).
Bacillus amyloliquefaciens is a species of bacterium in the genus Bacillus that is the source of the BamHI restriction enzyme. It also synthesizes a natural antibiotic protein barnase, a widely studied ribonuclease that forms a famously tight complex with its intracellular inhibitor barstar, and plantazolicin, an antibiotic with selective activity against Bacillus anthracis.
Thiostrepton is a natural cyclic oligopeptide antibiotic of the thiopeptide class, derived from several strains of streptomycetes, such as Streptomyces azureus and Streptomyces laurentii. Thiostrepton is a natural product of the ribosomally synthesized and post-translationally modified peptide (RiPP) class.
Zwittermicin A is an antibiotic that has been identified from the bacterium Bacillus cereus UW85. It is a molecule of interest to agricultural industry because it has the potential to suppress plant disease due to its broad spectrum activity against certain gram positive and gram negative prokaryotic micro-organisms. The molecule is also of interest from a metabolic perspective because it represents a new structural class of antibiotic and suggests a crossover between polyketide and non-ribosomal peptide biosynthetic pathways. Zwittermicin A is linear aminopolyol.
Streptogramin A is a group of antibiotics within the larger family of antibiotics known as streptogramins. They are synthesized by the bacteria Streptomyces virginiae. The streptogramin family of antibiotics consists of two distinct groups: group A antibiotics contain a 23-membered unsaturated ring with lactone and peptide bonds while group B antibiotics are depsipeptides. While structurally different, these two groups of antibiotics act synergistically, providing greater antibiotic activity than the combined activity of the separate components. These antibiotics have until recently been commercially manufactured as feed additives in agriculture, although today there is increased interest in their ability to combat antibiotic-resistant bacteria, particularly vancomycin-resistant bacteria.
Patellamide A is a peptide natural product produced by Prochloron didemni, a cyanobacterial symbiont of Lissoclinum patella, and was first isolated in 1981. Patellamide A is one of many didemnid peptides. Other closely related peptides include patellamides B, C, and D and trunkamide. The patellamides and trunkamide show moderate cytotoxicity and activity against multidrug resistant cancer cell lines.
Radical SAM is a designation for a superfamily of enzymes that use a [4Fe-4S]+ cluster to reductively cleave S-adenosyl-L-methionine (SAM) to generate a radical, usually a 5′-deoxyadenosyl radical (5'-dAdo), as a critical intermediate. These enzymes utilize this radical intermediate to perform diverse transformations, often to functionalize unactivated C-H bonds. Radical SAM enzymes are involved in cofactor biosynthesis, enzyme activation, peptide modification, post-transcriptional and post-translational modifications, metalloprotein cluster formation, tRNA modification, lipid metabolism, biosynthesis of antibiotics and natural products etc. The vast majority of known radical SAM enzymes belong to the radical SAM superfamily, and have a cysteine-rich motif that matches or resembles CxxxCxxC. rSAMs comprise the largest superfamily of metal-containing enzymes.
Bacillibactin is a catechol-based siderophore secreted by members of the genus Bacillus, including Bacillus anthracis and Bacillus subtilis. It is involved in the chelation of ferric iron (Fe3+) from the surrounding environment and is subsequently transferred into the bacterial cytoplasm via the use of ABC transporters.
Bottromycin is a macrocyclic peptide with antibiotic activity. It was first discovered in 1957 as a natural product isolated from Streptomyces bottropensis. It has been shown to inhibit methicillin-resistant Staphylococcus aureus (MRSA) and vancomycin-resistant Enterococci (VRE) among other Gram-positive bacteria and mycoplasma. Bottromycin is structurally distinct from both vancomycin, a glycopeptide antibiotic, and methicillin, a beta-lactam antibiotic.
YcaO is a protein found in bacteria which is involved in the synthesis of thiazole/oxazole modified microcin antibiotics, such as bottromycin. YcaO performs ATP dependent cyclodehydration to form the oxazole and thiazole moieties of the microcin.
Ribosomally synthesized and post-translationally modified peptides (RiPPs), also known as ribosomal natural products, are a diverse class of natural products of ribosomal origin. Consisting of more than 20 sub-classes, RiPPs are produced by a variety of organisms, including prokaryotes, eukaryotes, and archaea, and they possess a wide range of biological functions.
The cyclothiazomycins are a group of natural products, classified as thiopeptides, which are produced by various Streptomyces species of bacteria.
Nosiheptide is a thiopeptide antibiotic produced by the bacterium Streptomyces actuosus.
The microviridins are a class of serine protease inhibitors produced by various genera of cyanobacteria. Recent genome mining has shown that the biosynthetic gene cluster responsible for microviridin biosynthesis is much more prevalent, found in many species of Pseudomonadota and Bacteriodota.
Thiopeptides are a class of peptide antibiotics produced by bacteria. They have antibiotic activity against Gram-positive bacteria, but little or no activity against Gram-negative bacteria. Many of the members of this class show activity against methicillin-resistant Staphylococcus aureus (MRSA) and are therefore subjects of research interest.
Klebsazolicin (KLB) is a peptide antibiotic encoded in the genome of a gram-negative bacterium Klebsiella pneumoniae subsp. ozonae and targeting prokaryotic ribosome. Klebsazolicin is a ribosomally synthesized and post-translationally modified peptide (RiPP) and a linear azol(in)e-containing peptide (LAP).
