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Ansamycin
Ansamycins is a family of bacterial secondary metabolites that show antimicrobial activity against many Gram-positive and some Gram-negative bacteria, and includes various compounds, including streptovaricins and rifamycins. In addition, these compounds demonstrate antiviral activity towards bacteriophages and poxviruses. Structure They are named ansamycins (from the Latin ansa, ''handle'') because of their unique structure, which consists of an aromatic moiety bridged by an aliphatic chain. The main difference between various derivatives of ansamycins is the aromatic moiety, which can be a naphthalene ring or a naphthoquinone ring as in rifamycin and the naphthomycins. Another variation consists of benzene or a benzoquinone ring system as in geldanamycin or ansamitocin. Ansamycins were first discovered in 1959 by Sensi et al. from '' Amycolatopsis mediterranei'', an actinomycete bacterium. Examples Rifamycins are a subclass of ansamycins with high potency against mycobact ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Naphthomycin
Naphthomycins are a group of closely related antimicrobial chemical compounds isolated from ''Streptomyces''. They are considered a subclass of ansamycin Ansamycins is a family of bacterial secondary metabolites that show antimicrobial activity against many Gram-positive and some Gram-negative bacteria, and includes various compounds, including streptovaricins and rifamycins. In addition, these c ...s. Members include: * Naphthomycin A * Naphthomycin B * Naphthomycin C * Naphthomycin D * Naphthomycin E * Naphthomycin F * Naphthomycin G * Naphthomycin H * Naphthomycin I * Naphthomycin J * Naphthomycin K * Naphthomycin L * Naphthomycin M * Naphthomycin N Chemical structures File:Naphthomycin A.svg, Naphthomycin A File:Naphthomycin B.svg, Naphthomycin B File:Naphthomycin C.svg, Naphthomycin C File:Naphthomycin D.svg, Naphthomycin D File:Naphthomycin E.svg, Naphthomycin E File:Naphthomycin F.svg, Naphthomycin F File:Naphthomycin G.svg, Naphthomycin G References {{reflist Ant ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rifamycins
The rifamycins are a group of antibiotics that are synthesized either naturally by the bacterium ''Amycolatopsis rifamycinica'' or artificially. They are a subclass of the larger family of ansamycins. Rifamycins are particularly effective against mycobacteria, and are therefore used to treat tuberculosis, leprosy, and mycobacterium avium complex (MAC) infections. The rifamycin group includes the "classic" rifamycin drugs as well as the rifamycin derivatives rifampicin (or rifampin), rifabutin, rifapentine, rifalazil and rifaximin. Rifamycin, sold under the trade name Aemcolo, is approved in the United States for treatment of travelers' diarrhea in some circumstances. Bacterium ''Streptomyces mediterranei'' was first isolated in 1957 from a soil sample collected near the beach-side town of St Raphael in southern France. The name was originally given by two microbiologists working with the Italian drug company Group Lepetit SpA in Milan, the Italian Grazia Beretta, and Pinha ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Geldanamycin
Geldanamycin is a 1,4-benzoquinone ansamycin antitumor antibiotic that inhibits the function of Hsp90 (Heat Shock Protein 90) by binding to the unusual ADP/ATP-binding pocket of the protein. HSP90 client proteins play important roles in the regulation of the cell cycle, cell growth, cell survival, apoptosis, angiogenesis and oncogenesis. Geldanamycin induces the degradation of proteins that are mutated or overexpressed in tumor cells such as v-Src, Bcr-Abl, p53, and ERBB2. This effect is mediated via HSP90. Despite its potent antitumor potential, geldanamycin presents several major drawbacks as a drug candidate such as hepatotoxicity, further, Jilani ''et al.''. reported that geldanamycin induces the apoptosis of erythrocytes under physiological concentrations. These side effects have led to the development of geldanamycin analogues, in particular analogues containing a derivatisation at the 17 position: * 17-AAG * 17-DMAG Biosynthesis Geldanamycin was originally discover ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Streptovaricins
Streptovaricins are a group of structurally related macrolide antibiotics. They belong to the larger class of antibiotics known as ansamycin Ansamycins is a family of bacterial secondary metabolites that show antimicrobial activity against many Gram-positive and some Gram-negative bacteria, and includes various compounds, including streptovaricins and rifamycins. In addition, these c ...s. References Macrolide antibiotics Ansamycins {{antibiotic-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Geldanamycin
Geldanamycin is a 1,4-benzoquinone ansamycin antitumor antibiotic that inhibits the function of Hsp90 (Heat Shock Protein 90) by binding to the unusual ADP/ATP-binding pocket of the protein. HSP90 client proteins play important roles in the regulation of the cell cycle, cell growth, cell survival, apoptosis, angiogenesis and oncogenesis. Geldanamycin induces the degradation of proteins that are mutated or overexpressed in tumor cells such as v-Src, Bcr-Abl, p53, and ERBB2. This effect is mediated via HSP90. Despite its potent antitumor potential, geldanamycin presents several major drawbacks as a drug candidate such as hepatotoxicity, further, Jilani ''et al.''. reported that geldanamycin induces the apoptosis of erythrocytes under physiological concentrations. These side effects have led to the development of geldanamycin analogues, in particular analogues containing a derivatisation at the 17 position: * 17-AAG * 17-DMAG Biosynthesis Geldanamycin was originally discover ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Naphthalene
Naphthalene is an organic compound with formula . It is the simplest polycyclic aromatic hydrocarbon, and is a white crystalline solid with a characteristic odor that is detectable at concentrations as low as 0.08 ppm by mass. As an aromatic hydrocarbon, naphthalene's structure consists of a fused pair of benzene rings. It is best known as the main ingredient of traditional mothballs. History In the early 1820s, two separate reports described a white solid with a pungent odor derived from the distillation of coal tar. In 1821, John Kidd cited these two disclosures and then described many of this substance's properties and the means of its production. He proposed the name ''naphthaline'', as it had been derived from a kind of naphtha (a broad term encompassing any volatile, flammable liquid hydrocarbon mixture, including coal tar). Naphthalene's chemical formula was determined by Michael Faraday in 1826. The structure of two fused benzene rings was proposed by Emil Erlen ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Leprosy
Leprosy, also known as Hansen's disease (HD), is a long-term infection by the bacteria '' Mycobacterium leprae'' or '' Mycobacterium lepromatosis''. Infection can lead to damage of the nerves, respiratory tract, skin, and eyes. This nerve damage may result in a lack of ability to feel pain, which can lead to the loss of parts of a person's extremities from repeated injuries or infection through unnoticed wounds. An infected person may also experience muscle weakness and poor eyesight. Leprosy symptoms may begin within one year, but, for some people, symptoms may take 20 years or more to occur. Leprosy is spread between people, although extensive contact is necessary. Leprosy has a low pathogenicity, and 95% of people who contract ''M. leprae'' do not develop the disease. Spread is thought to occur through a cough or contact with fluid from the nose of a person infected by leprosy. Genetic factors and immune function play a role in how easily a person catches the disease. L ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ethers
In organic chemistry, ethers are a class of compounds that contain an ether group—an oxygen atom connected to two alkyl or aryl groups. They have the general formula , where R and R′ represent the alkyl or aryl groups. Ethers can again be classified into two varieties: if the alkyl or aryl groups are the same on both sides of the oxygen atom, then it is a simple or symmetrical ether, whereas if they are different, the ethers are called mixed or unsymmetrical ethers. A typical example of the first group is the solvent and anaesthetic diethyl ether, commonly referred to simply as "ether" (). Ethers are common in organic chemistry and even more prevalent in biochemistry, as they are common linkages in carbohydrates and lignin. Structure and bonding Ethers feature bent C–O–C linkages. In dimethyl ether, the bond angle is 111° and C–O distances are 141 pm. The barrier to rotation about the C–O bonds is low. The bonding of oxygen in ethers, alcohols, and water ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lactams
A lactam is a cyclic amide, formally derived from an amino alkanoic acid. The term is a portmanteau of the words ''lactone'' + ''amide''. Nomenclature Greek prefixes in alphabetical order indicate ring size: * α-Lactam (3-atom rings) * β-Lactam (4-atom rings) * γ-Lactam (5-atom rings) * δ-Lactam (6-atom rings) * ε-Lactam (7-atom rings) This ring-size nomenclature stems from the fact that a hydrolyzed α-Lactam leads to an α-amino acid and a β-Lactam to a β-amino acid, ''etc''. Synthesis General synthetic methods exist for the organic synthesis of lactams. Beckmann rearrangement Lactams form by the acid-catalyzed rearrangement of oximes in the Beckmann rearrangement. Schmidt reaction Lactams form from cyclic ketones and hydrazoic acid in the Schmidt reaction. Cyclization of amino acids Lactams can be formed from cyclisation of amino acids via the coupling between an amine and a carboxylic acid within the same molecule. Lactamization is most efficient in thi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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