Vancomycin is a glycopeptide antibiotic medication used to treat a number of bacterial infections. It is used intravenously as a treatment for complicated skin infections, bloodstream infections, endocarditis, bone and joint infections, and meningitis caused by methicillin-resistant Staphylococcus aureus. Blood levels may be measured to determine the correct dose. Vancomycin is also taken orally as a treatment for severe Clostridium difficile colitis. When taken orally it is poorly absorbed.
Alamethicin is a channel-forming peptide antibiotic, produced by the fungus Trichoderma viride. It belongs to peptaibol peptides which contain the non-proteinogenic amino acid residue Aib. This residue strongly induces formation of alpha-helical structure. The peptide sequence is
Mupirocin, sold under the brand name Bactroban among others, is a topical antibiotic useful against superficial skin infections such as impetigo or folliculitis. It may also be used to get rid of methicillin-resistant S. aureus (MRSA) when present in the nose without symptoms. Due to concerns of developing resistance, use for greater than ten days is not recommended. It is used as a cream or ointment applied to the skin.
Teicoplanin is an semisynthetic glycopeptide antibiotic with a spectrum of activity similar to vancomycin. Its mechanism of action is to inhibit bacterial cell wall peptidoglycan synthesis. It is used in the prophylaxis and treatment of serious infections caused by Gram-positive bacteria, including methicillin-resistant Staphylococcus aureus and Enterococcus faecalis.
Bleomycin is a medication used to treat cancer. This includes Hodgkin's lymphoma, non-Hodgkin's lymphoma, testicular cancer, ovarian cancer, and cervical cancer among others. Typically used with other cancer medications, it can be given intravenously, by injection into a muscle or under the skin. It may also be administered inside the chest to help prevent the recurrence of a pleural effusion due to cancer; however talc is better for this.
In organic chemistry, polyketides are a class of natural products derived from a precursor molecule consisting of a chain of alternating ketone and methylene groups: [−C(=O)−CH2−]n. First studied in the early 20th century, discovery, biosynthesis, and application of polyketides has evolved. It is a large and diverse group of secondary metabolites caused by its complex biosynthesis which resembles that of fatty acid synthesis. Because of this diversity, polyketides can have various medicinal, agricultural, and industrial applications. Many polyketides are medicinal or exhibit acute toxicity. Biotechnology has enabled discovery of more naturally-occurring polyketides and evolution of new polyketides with novel or improved bioactivity.
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.
Dalfopristin is a semi-synthetic streptogramin antibiotic analogue of ostreogyrcin A. The combination quinupristin/dalfopristin was brought to the market by Rhone-Poulenc Rorer Pharmaceuticals in 1999. Synercid is used to treat infections by staphylococci and by vancomycin-resistant Enterococcus faecium.
Didemnins are cyclic depsipeptide compounds isolated from a tunicate of the genus Trididemnum that were collected in the Caribbean Sea. They were first isolated in 1978 at the University of Illinois.
Polyketide synthases (PKSs) are a family of multi-domain enzymes or enzyme complexes that produce polyketides, a large class of secondary metabolites, in bacteria, fungi, plants, and a few animal lineages. The biosyntheses of polyketides share striking similarities with fatty acid biosynthesis.
Doxorubicin (DXR) is a 14-hydroxylated version of daunorubicin, the immediate precursor of DXR in its biosynthetic pathway. Daunorubicin is more abundantly found as a natural product because it is produced by a number of different wild type strains of streptomyces. In contrast, only one known non-wild type species, streptomyces peucetius subspecies caesius ATCC 27952, was initially found to be capable of producing the more widely used doxorubicin. This strain was created by Arcamone et al. in 1969 by mutating a strain producing daunorubicin, but not DXR, at least in detectable quantities. Subsequently, Hutchinson's group showed that under special environmental conditions, or by the introduction of genetic modifications, other strains of streptomyces can produce doxorubicin. His group has also cloned many of the genes required for DXR production, although not all of them have been fully characterized. In 1996, Strohl's group discovered, isolated and characterized dox A, the gene encoding the enzyme that converts daunorubicin into DXR. By 1999, they produced recombinant Dox A, a Cytochrome P450 oxidase, and found that it catalyzes multiple steps in DXR biosynthesis, including steps leading to daunorubicin. This was significant because it became clear that all daunorubicin producing strains have the necessary genes to produce DXR, the much more therapeutically important of the two. Hutchinson's group went on to develop methods to improve the yield of DXR, from the fermentation process used in its commercial production, not only by introducing Dox A encoding plasmids, but also by introducing mutations to deactivate enzymes that shunt DXR precursors to less useful products, for example baumycin-like glycosides. Some triple mutants, that also over-expressed Dox A, were able to double the yield of DXR. This is of more than academic interest because at that time DXR cost about $1.37 million per kg and current production in 1999 was 225 kg per annum. More efficient production techniques have brought the price down to $1.1 million per kg for the non-liposomal formulation. Although DXR can be produced semi-synthetically from daunorubicin, the process involves electrophilic bromination and multiple steps and the yield is poor. Since daunorubicin is produced by fermentation, it would be ideal if the bacteria could complete DXR synthesis more effectively.
A protein synthesis inhibitor is a compound that stops or slows the growth or proliferation of cells by disrupting the processes that lead directly to the generation of new proteins.
Streptogramin B is a subgroup of the streptogramin antibiotics family. These natural products are cyclic hexa- or hepta depsipeptides produced by various members of the genus of bacteria Streptomyces. Many of the members of the streptogramins reported in the literature have the same structure and different names; for example, pristinamycin IA = vernamycin Bα = mikamycin B = osteogrycin B.
Tirandamycins are a small group of natural products that contain a bicyclic ketal system and a tetramic acid moiety, the latter of which is found in different natural products from a variety of sources and which is characterized by a 2,4-pyrrolidinedione ring system. Members of this structural family have shown a wide range of biological activities like in antiparasitic, antifungal and anti-HIV evaluations, and furthermore, have shown potential usefulness because of their potent antibacterial properties. Streptolydigin, an analogue of the tirandamycins, is known to function as an antibacterial agent through inhibiting the chain initiation and elongation steps RNA polymerase transcription. The structural diversity in the tirandamycin family originates from the different oxidation patterns observed in the bicycic ketal system, and these modifications are determinant features for the bioactivity associated with these molecules.
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.
Curacin A is a hybrid polyketide synthase (PKS)/nonribosomal peptide synthase (NRPS) derived natural product produced isolated from the cyanobacterium Lyngbya majuscula. Curacin A belongs to a family of natural products including jamaicamide, mupirocin, and pederin that have an unusual terminal alkene. Additionally, Curacin A contains a notable thiazoline ring and a unique cyclopropyl moiety, which is essential to the compound's biological activity. Curacin A has been characterized as potent antiproliferative cytotoxic compound with notable anticancer activity for several cancer lines including renal, colon, and breast cancer. Curacin A has been shown to interact with colchicine binding sites on tubulin, which inhibits microtubule polymerization, an essential process for cell division and proliferation.
C-1027 or lidamycin is an antitumor antibiotic consisting of a complex of an enediyne chromophore and an apoprotein. It shows antibiotic activity against most Gram-positive bacteria. It is one of the most potent cytotoxic molecules known, due to its induction of a higher ratio of DNA double-strand breaks than single-strand breaks.
Pyoluteorin is a natural antibiotic that is biosynthesized from a hybrid nonribosomal peptide synthetase (NRPS) and polyketide synthase (PKS) pathway. Pyoluteorin was first isolated in the 1950s from Pseudomonas aeruginosa strains T359 and IFO 3455 and was found to be toxic against oomycetes, bacteria, fungi, and against certain plants. Pyoluteorin is most notable for its toxicity against the oomycete Pythium ultimum, which is a plant pathogen that causes a global loss in agriculture. Currently, pyoluteorin derivatives are being studied as an Mcl-1 antagonist in order to target cancers that have elevated Mcl-1 levels.
Chloroeremomycin is a member of the glycopeptide family of antibiotics, such as vancomycin. The molecule is a non-ribosomal polypeptide that has been glycosylated. It is composed of seven amino acids and three saccharide units. Although chloroeremomycin has never been in clinical phases, oritavancin, a semi-synthetic derivative of chloroeremomycin, has been investigated.
Andrimid is an antibiotic natural product that is produced by the marine bacterium Vibrio coralliilyticus. Andrimid is an inhibitor of fatty acid biosynthesis by blocking the carboxyl transfer reaction of acetyl-CoA carboxylase (ACC).
