Macbecin

Macbecins are a pair of chemical compounds in the ansamycin family of antibiotics. They are designated macbecin I and macbecin II and they were first isolated from actinomycete bacteria. Macbecin possesses antitumor properties. In vitro studies have shown that macbecins are effective in the eradication of Gram-positive bacteria, fungi, and protozoa including Tetrahymena pyriformis.

Structure
Macbecins have an unusual macrocyclic lactam structure. The two variants, macbecin I and II, correspond to the oxidized 1,4-benzoquinone and reduced hydroquinone, respectively.

Mechanism of action
Macbecins mechanism of action is in part due to heat shock protein Hsp90 protein inhibition.