- Ansamycin
Ansamycins is a family of secondary metabolites that show
antimicrobial activity against manygram-positive and somegram-negative bacteria and includes various compounds among which:streptovaricins andrifamycins [cite journal |author=Wehrli, W.; Staehelin, M. |journal=Bacteriol. Rev. |title=Actions of the rifamycins |volume=35 |pages=290 |year=1971] . In addition, these compounds demonstrate antiviral activity towards bacteriophages andpoxviruses .tructure
They are named ansamycins—"ansa" from the Latin for handle—because of their unique structure which comprises an aromatic moiety bridged by an aliphatic chain [cite journal |author=Prelog, V.; Oppolzer, W. |journal=Helv. Chim. Acta. |title=Rifamycins. 4. Ansamycins, a novel class of microbial metabolism products |volume=56 |pages=2279 |year=1973] . The main difference between various derivatives of ansamycins is the aromatic moiety, which can be a
naphthalene ring or anaphthoquinone ring as inrifamycin andnaphthomycin [cite journal |author=Balerna, M.; Keller-Schierlein, W.; Martius, C.; Wolf, H.; Zähner, H. |journal=Arch. Mikrobiol. |title=Metabolic products of microorganisms. 72. Naphthomycin, an antimetabolite of vitamin K |volume=65 |pages=303 |year=1969] .Another variation comprises 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. [cite journal |author=Sensi, P.; Margalith, P.; Timbal, M. T. |journal=Ed. Sci. |title=Rifomycin, a new antibiotic; preliminary report |volume=14 |pages=146 |year=1959]Examples
Rifamycins are a subclass of ansamycins with high potency against mycobacterial activity. This resulted in their wide use in the treatment of
tuberculosis ,leprosy , and AIDS-related mycobacterial infections. [cite journal |author=Floss, H. G.; Yu, T. |journal=Curr. Opin. Chem. Biol. |title=Lessons from the rifamycin biosynthetic gene cluster |volume=3 |pages=592 |year=1999 |doi=10.1016/S1367-5931(99)00014-9] Since then various analogues have been isolated from other prokaryotes.References
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